56372 T H E W O R L D B A N K Public Health Surveillance Toolkit A guide for busy task managers Anabela Garcia-Abreu William Halperin Isabella Danel PUBLIC HEALTH SURVEILLANCE TOOLKIT Anabela Garcia-Abreu, William Halperin, and Isabella Danel World Bank February 2002 i This publication was prepared the the Development Communications Division, External Affairs Vice-Presidency, The World Bank. The findings, conclusions and recommendations expressed in this document do not necessarily reflect the official viewpoint of the World Bank. Copyright 2002 by the Development Communications Division External Affairs Vice-Presidency The World Bank. ii CONTENTS Preface .............................................................................................................................. ix Acknowledgments ........................................................................................................... xi Abbreviations and Acronyms .......................................................................................... xiii Background ....................................................................................................................... 1 Part A Public Health Surveillance: Questions and Answers ......................................... 3 What is public health surveillance? ................................................................................... 3 What are the goals of public health surveillance? ............................................................. 4 Why invest in surveillance? ............................................................................................... 6 What is the spectrum of outcomes amenable to surveillance? .......................................... 7 What are the major surveillance methods? ........................................................................ 9 What is the difference between surveillance and health information systems? ................. 11 What is the difference between vertical and integrated surveillance systems? ................. 11 What is active versus passive surveillance? ....................................................................... 12 What are important issues when considering sources for surveillance data? .................... 12 What are the considerations in planning public health surveillance? ................................ 13 What conditions lend themselves to successful surveillance programs? ........................... 13 What data should be collected? ......................................................................................... 14 Are there stages of development in a public health surveillance system? ......................... 15 What systems are used for data transmittal? ...................................................................... 16 What are the common issues in communication of surveillance results?.......................... 16 What is the relationship between laboratories and surveillance? ...................................... 17 How do you evaluate the surveillance system?.................................................................. 18 What are the components of an effective surveillance program? ...................................... 18 What are the issues of data privacy and accessibility for use? .......................................... 18 Is a legal basis for public health surveillance necessary? .................................................. 19 How are outbreaks recognized? ......................................................................................... 19 How do I complete the surveillance process? .................................................................... 20 Appendix A.1 What Software Is Available for Surveillance? ....................................... 21 Appendix A.2 What Are International Sources of Surveillance Information? ............ 23 iii Appendix A.3 What Global and Regional Alert Systems Exist? .................................... 25 Appendix A.4 What Training Is Available? ...................................................................... 27 Appendix A.5 Where Can I Find Useful Textbooks and Articles on Surveillance? ....... 29 Appendix A.6 How Are Surveillance Systems Evaluated? ............................................. 31 Appendix A.7 What Are the Key Statistical Concepts for Surveillance? ...................... 35 Appendix A.8 How Does Surveillance Case Definition Relate to Sensitivity and Specificity? .................................................................................................................... 37 Part B How to Prepare a Surveillance Project: Operational Aspects ........................... 39 Where do I begin? .............................................................................................................. 39 Do I need to know all health data systems that exist in the country? ................................ 39 Current system needs assessment. What should I look for? .............................................. 39 Communicable Disease Surveillance Systems .................................................................. 40 Noncommunicable diseases and behavioral and other risk factor surveillance ................. 41 Laboratory network............................................................................................................ 43 Information and telecommunications system .................................................................... 43 What are some general issues and needs of the surveillance system? ............................... 45 Regulatory aspects ............................................................................................................. 46 What are the main decisions and options for project implementation? ............................. 47 What about the economic analysis? ................................................................................... 48 Sustainability analysis ........................................................................................................ 48 What expertise do I need on missions? .............................................................................. 49 Where can I look for this expertise? .................................................................................. 49 National stakeholders need to be involved, right? ............................................................. 49 How do I involve the stakeholders in the process? ............................................................ 49 What are the staffing needs? .............................................................................................. 50 What are the most common training needs? ...................................................................... 51 What are the most common budget lines for public health surveillance? ......................... 51 How can I assess project progress and impact? ................................................................. 51 Progress .............................................................................................................................. 51 Impact ................................................................................................................................ 51 iv What about project evaluation? ......................................................................................... 54 What are the most common problems in surveillance systems? ....................................... 54 What are the main conditions for successful project implementation? ............................. 55 Appendix B.1 Evaluation of the system and capacity ................................................... 57 Appendix B.2 Stakeholder Workshops ............................................................................ 59 Appendix B.3 Sample Terms of Reference for Specialists Participating in Preparation Missions ................................................................................................... 61 Appendix B.4 Specific Disease Surveillance “Tips” ........................................................ 65 Why are behaviors and noncommunicable diseases important? ....................................... 65 How can NCDs be prevented? ........................................................................................... 65 What is behavioral risk factor surveillance? ...................................................................... 65 Are behaviors important only for noncommunicable diseases? ........................................ 65 What are youth surveys? .................................................................................................... 65 What conditions should be reported? ................................................................................ 66 What information should be collected on these persons? .................................................. 66 Who should report? ............................................................................................................ 66 How should they report? .................................................................................................... 66 What are some of the key factors in a successful HIV/AIDS surveillance system? ......... 66 What other sources of data may be useful in describing the HIV epidemic? .................... 66 What is the role of HIV serosurveys (HIV sentinel surveillance) in describing the status of a country’s HIV epidemic? ......................................................................................... 66 Case detection .................................................................................................................... 67 Treatment ........................................................................................................................... 67 Surveys to measure drug-resistant TB, HIV-TB, and trends in TB infection and prevalence ....................................................................................................................... 67 What are vital statistics? .................................................................................................... 69 What are Millennium Development Goals? ...................................................................... 69 How is infant mortality measured and what is its importance at the local level?.............. 69 How is maternal mortality measured? ............................................................................... 69 How is infant and maternal mortality surveillance carried out? ........................................ 69 What are obstacles and incentives to improving vital statistics? ....................................... 69 Appendix B.5 The Who STEPwise Approach To Risk Factor Surveillance .................... 73 v Appendix B.6 Surveillance Processes and Task by Level .............................................. 75 Appendix B.7 Surveillance Glossary ............................................................................... 77 References ........................................................................................................................ 81 Figures Figure 1 Integrated approach to communicable disease surveillance ................................ 11 Figure 2 The WHO’s STEPwise Approach ........................................................................ 73 Figure 3 Surveillance Processes and Task by Level........................................................... 75 Tables Table 1 Levels where surveillance activities are performed .............................................. 4 Table 2 Scheme for developing and expanding a list for mandatory disease reporting .... 8 Table 3 Major surveillance methods .................................................................................. 9 Table 4 Feasible surveillance system characteristics relative to different resource levels ............................................................................................................................... 15 Table 5 Factors leading to usefulness or ineffectiveness of surveillance systems ............. 19 Table 6 Comparison of a survey test with a reference test ................................................ 36 Table 7 Training and targeted personnel ............................................................................ 52 Table 8 Common budget lines for public health surveillance ........................................... 53 Table 9 Sample agenda for workshop ................................................................................ 60 Boxes Box 1 Surveillance is not research ..................................................................................... 4 Box 2 Key elements of surveillance systems .................................................................... 5 Box 3 Uses for surveillance ............................................................................................... 5 Box 4 Primary, secondary, and tertiary prevention in public health .................................. 6 Box 5 Criteria for disease selection ................................................................................... 14 Box 6 Lessons learned from Jean-Jacques de St. Antoine, Task Manager for Brazil’s disease surveillance project (VIGISUS) ......................................................................... 46 Box 7 Lessons learned from Marcel O. Borman, Coordinator for the Public Health Surveillance and Disease Control Project in Argentina (VIGI-A) ................................. 50 Box 8 Lessons learned from Jarbas Barbosa da Silva, Jr., Director of the National Epidemiology Department of Brazil............................................................................... 55 Box 9 Behavioral risk factor surveillance ......................................................................... 65 vi Box 10 HIV/AIDS surveillance ......................................................................................... 66 Box 11 Surveillance in tuberculosis control ...................................................................... 67 Box 12 Malaria surveillance ................................................................................................ 68 Box 13 Vital statistics and surveillance of the Millennium Development Goals: Infant and maternal mortality ........................................................................................... 69 Box 14 Avian and Human Influenza Surveillance ............................................................... 70 vii viii PREFACE T here is growing international awareness that efforts to reduce disease are facilitated by effective public health surveillance systems. This has led to countries being increasingly interested in the need for and benefits of public health surveillance, and to a greater demand for technical assistance and financing. Public health surveillance is important for governments in fulfilling their stewardship responsibili- ties. Countries’ health priorities include controlling, reducing, and preventing diseases; surveillance is a key strategy for them to be able to achieve those priorities. Public health surveillance has been identified as an essential public health function by the World Health Organization (WHO) Delphi study, the Pan American Health Organization (PAHO) for the region of the Americas, and by the U.S. Centers for Disease Control and Prevention (CDC) (Beltcher, Sapirie, and Goon 1998). Surveillance is noted as a public good and one of the core public health functions in the World Bank public health strategy note (Claeson and others 2002). Outputs from surveillance could be critical for monitoring and evaluation in the poverty reduction strategy paper process, for measuring progress toward Mil- lennium Development Goals (MDGs), as well as for assessing the status of individual Bank health projects. The World Bank, the Inter-American Development Bank (IDB), and the PAHO have formulated a Shared Agenda for Health in the Americas as a way of institutionalizing coordinated and complementary ef- forts that benefit from the comparative advantages of each of the three institutions. One of the areas of common work in this Shared Agenda is public health surveillance. The PAHO has a long history of technical cooperation in developing infrastructure for surveillance in general, and for selected communicable diseases in particular. Notably successful systems have been developed for vaccine-preventable diseases. Multiple projects financed through bilateral and multilateral agencies have been implemented with the PAHO’s technical and management support. The World Bank has financed two projects to date that are entirely focused on surveillance, and another has been funded by the IDB. There are also several other loans with surveillance compo- nents. As interest in such loans increases, there is a need to share experiences and best practices. To collaborate in strengthening surveillance systems internationally, we need to better prepare Bank staff. The development of this toolkit contributes to that effort. This toolkit draws on the expertise of public health practitioners who have experience with public health surveillance and who have recognized the core role of surveillance in public health. These practitioners have advocated for surveillance programs, supplied innovative ideas, and provided insightful critiques over many years. This toolkit also draws on the experience of Bank staff and ix technical experts from the PAHO and the CDC who have contributed to Bank missions. The toolkit also makes use of WHO references, primarily those from the WHO’s Web site (www.who.int/emc/ surveill/index.html). x ACKNOWLEDGMENTS T his report was drawn from multiple authoritative sources and experiences of people working with surveillance. The team consisted of Anabela Garcia-Abreu (Task Team Leader), William Halperin (consultant), Isabella Danel, and Marian Kaminskis (editing and formatting). Peer review- ers were Charles Griffin (World Bank), Marlo Libel (PAHO), Steve Ostroff (CDC), and Daniel Miller (CDC). Thank you for their careful review and comments. Our thanks also to Kathleen Gallagher, Lawrence Barat, and Meade Morgan (CDC) for the HIV/ AIDS, Malaria surveillance, and telecommunication system information respectively, as well as Jean Jacques de St. Antoine, Jarbas Barbosa, and Marcelo Bortman for contributing lessons learned, to Robert Mullan ( PH consultant, Atlanta, GA) for his written contributions on the first part, and Mariam Claeson and Diane Weil for comments provided. This paper was funded by Dutch Trust Fund and Public Health Thematic Group. xi xii ABBREVIATIONS AND ACRONYMS AFP Acute flaccid paralysis AIDS Acquired immune deficiency syndrome ARI Acute respiratory infection BCG Bacille Calmette-Guerin BRF Behavioral risk factor BRFSS Behavioral Risk Factor Surveillance System CDC Centers for Disease Control and Prevention DALYs Disability-adjusted life years DHS Demographic and Health Surveys FETP Field Epidemiology Training Program GIS Geographic information system HIV Human immunodeficiency virus IBRD International Bank for Reconstruction and Development IDB Inter-American Development Bank IMR Infant mortality rate MDG Millennium Development Goal MMWR Morbidity and Mortality Weekly Report (of the CDC) MoH Ministry of health MMR Maternal mortality rate NCD Noncommunicable disease NGO Nongovernmental organization ORS Oral rehydration solution PAHO Pan-American Health Organization PHTN Public Health Training Network STEPS STEPwise approach to risk factor surveillance STI Sexually transmitted infection TB Tuberculosis TEPHINET Training Programs in Epidemiology and Public Health Intervention Network, Inc. VIGI-A Public Health Surveillance and Disease Control project in Argentina VIGISUS Public Health Surveillance and Disease Control Project in Brazil WHO World Health Organization WISQARSTM Web-based Injury Statistics Query and Reporting System YPLL Years of potential life lost xiii xiv BACKGROUND T he audience for this toolkit is World Bank Task Managers and their counterparts in other or- ganizations—those who, in response to requests, go This toolkit will focus on a range of potential sur- veillance activities, recognizing that there are cost and work force considerations in establishing a sur- to countries, assess the problems, design projects veillance system in any given country. to address these problems, and implement or su- pervise these projects. Most World Bank staff are Part A of this toolkit provides some theoretical con- already overloaded with work and do not have the cepts, and knowledge about surveillance that has time to read material that is impractical or research- been gained through applying these concepts and oriented. Many have little or no background in the practice of surveillance in developing countries. public health or surveillance, which further com- A moderate number of sources are cited so that the plicates the situation. more curious reader might have a guide to primary sources (see appendix A.5). Additional information It is the goal of this toolkit to present fundamental can be found in the other appendixes. concepts for surveillance in public health. After they have read this document project teams should be Part B provides information that will be useful to able to critically assess the public health surveillance Task Managers as they prepare loans for strength- system (or systems) currently operating in a given ening public health surveillance systems. Several country, and have some idea of ways to improve World Bank experiences are shared. The focus of part these systems. The World Bank operates in coun- B is on practical aspects of surveillance and on les- tries with varying economic states of development. sons learned. 1 2 PART A Public Health Surveillance: Questions and Answers Good surveillance does not necessarily ensure the making of right decisions, but it reduces the chances of making the wrong ones. Alexander D. Langmuir (Langmuir 1963).1 What is public health surveillance? There have been three developments in the concep- tion and definition of surveillance. The original concept development was the watching and confine- Surveillance is defined as the “ongoing ment of individual cases of highly communicable systematic collection, collation, analysis, diseases responsible for devastating epidemics, in and interpretation of data; and the dis- particular smallpox and yellow fever. semination of information to those who need to know in order that action be The object of watchfulness was moved from the in- taken” (www.who.int/emc/ surveill/ dividual to the surveillance of epidemic diseases in index.html). populations during the mid-20th century, largely due to the work of Alexander Langmuir (Langmuir 1976; A more complete definition of surveillance Fowler 1993; Fowler 1994; Chorba and others 1989). is: The ongoing systematic collection, analysis, and interpretation of health data Finally, the concept of public health action was essential to the planning, implementation, clearly attached to surveillance. Action is what dis- and evaluation of public health practice, tinguishes surveillance from the task of simply closely integrated with the timely dissemi- monitoring events. Donald Henderson, who was in- nation of these data to those who need to strumental in the eradication of smallpox in the know. The final link in the surveillance 1970s, once described surveillance as the “neurologic chain is the application of these data to system of public health.” Surveillance, the eyes and prevention and control. A surveillance sys- ears of public health, provides information through tem includes a functional capacity for which public health programs can act effectively and data collection, analysis, and dissemina- efficiently. Controlling and preventing diseases based tion linked to public health programs on information collected through surveillance re- (CDC 1988). quires action. In some cases actions must be immediate—within hours—in order to prevent large- 1 Dr. Langmuir (1910–1993) was a surveillance expert and chief epidemiologist at CDC for more than 20 years. He was also founder of the U.S. epidemic intelligence service. 3 Public Health Surveillance: Questions and Answers Box 1. What are the goals of public health SURVEILLANCE IS NOT RESEARCH surveillance? The goals of surveillance often differ at the various Public health surveillance is essentially descriptive in nature. It administrative levels of the public health system describes the occurrence of injury or disease and its determi- nants in the population. It also leads to public health action. (Table 1; WHO 1999a). Surveillance data are used to Research, in contrast, is experimental in design, aimed at testing allocate resources and evaluate the impact of con- a hypothesis by comparing and contrasting groups. Surveillance trol and prevention strategies and programs at all data are usually limited in detail and price (that is, in the cost of levels. However, at the local level2 the use of surveil- obtaining the data), but may eventually be used to develop research hypotheses. Research data are often quite complex and lance to trigger basic public health investigations and detailed and are usually expensive to produce. If we confuse implement specific control activities predominates surveillance with research, we may be motivated to collect large for infectious diseases and environmental hazards. amounts of detailed data on each case. The burden of this In contrast, monitoring for trends, measuring the ef- approach is too great for the resources available for surveillance systems and usually leads to failure. fectiveness of specific interventions, and conducting more complicated analysis to elucidate risk factors predominate at the national level. At the local level scale epidemics and deaths (from, for instance, chol- analytic capacity is usually much more limited than era, meningitis, Ebola, or food contamination). In at the national level. At the state level3 public health others, control and prevention activities are long- agencies typically share both perspectives. term responses to information about diseases (such as tuberculosis [TB], acquired immune deficiency There are many types of surveillance systems, which syndrome [AIDS], malaria, and noncommunicable vary from very simple to complex. In general, in de- diseases such as diabetes and hypertension), and ac- veloping countries the use of less complex, more tion may be taken within days, weeks, or years. easily established, and sustainable systems are pre- Table 1. Levels Where Surveillance Activities Are Performed Activities National level State level Local level Detection and notification of cases — — Yes Collection and consolidation of case data Yes Yes Yes Analysis and interpretation Yes Yes Yes Investigation of cases and confirmation of diagnosis: • Epidemiologist — Yes — • Clinician — — Yes • Laboratory Yes Yes — Feedback Yes Yes Yes Dissemination Yes Yes Yes Action — = not usually Source: Adapted from WHO 1999b. 2 This toolkit will use the term “local level,” which is also referred to as the municipal, district, county, or jurisdictional level, among others. 3 This toolkit will use the term state level to refer to the intermediate level between national and local, which is also referred to as provincial, departmental, or regional, among others. 4 ferred. Examples of key elements of surveillance sys- Different goals require different approaches to data tems are provided in box 2. collection. Tradeoffs are necessary between timeli- ness and detail, and between achieving Box 2. representativeness and getting case reports for con- KEY ELEMENTS OF SURVEILLANCE SYSTEMS trol of transmission or exposure or other individualized interventions (Meriwether 1996). For All surveillance systems involve six key elements: example, at the local level a case of measles in a 1. Detection and notification of health event day-care center requires an immediate public health 2. Investigation and confirmation (epidemiological, response to prevent spread based on clinical find- clinical, laboratory) ings prior to laboratory confirmation. In contrast, 3. Collection of data only laboratory-confirmed cases and those cases that 4. Analysis and interpretation of data are epidemiologically linked to confirmed cases are 5. Feedback and dissemination of results used at the state and national levels to monitor 6. Response—a link to public health programs, progress toward measles elimination. specifically actions for prevention and control. Source: Adapted from WHO 1999a. In a similar way local public health authorities may review individual cases of infant mortality to as- sess gaps in the health-care delivery system and Central to the concept of surveillance is that any sys- obstacles to the implementation of community-based tem implemented serves as a stimulus to some action. prevention strategies. At the state level infant mor- Collection of data without an accompanying plan tality may be mapped using sophisticated geographic for using these data to address health problems is a information systems (GISs) not available locally to waste of resources. (Box 3) identify areas where further interventions should be targeted. At the national level cause-specific in- Box 3. fant mortality rates (IMRs) may be used to judge the effectiveness of nationwide strategies that pro- USES FOR SURVEILLANCE mote infant survival (such as oral rehydration Surveillance may be used to: solution (ORS), or Integrated Management of Child- • Recognize cases or clusters of cases to trigger interventions hood Illnesses (IMCI), vaccination, breast-feeding, to prevent transmission or reduce morbidity and mortality and clean deliveries). Cause-specific mortality rates (includes the special case in which surveillance at the are also used to modify recommendations as efforts national level is required to recognize multi-state clusters); to reduce infant mortality succeed and the causes • Assess the public health impact of health events or of infant mortality change. determine and measure trends; • Demonstrate the need for public health intervention programs and resources, and allocate resources during Surveillance often results in more targeted and public health planning; focused prevention activities. Such activities can • Monitor effectiveness of prevention and control measures be described as primary, secondary, or tertiary (see and intervention strategies; box 4). • Identify high-risk population groups or geographic areas to target interventions and guide analytic studies; and Surveillance systems play an important role at each • Develop hypotheses that lead to analytic studies about risk of the three prevention levels. An example at the factors for disease causation, propagation, or progression. primary protection level would be surveys of im- 5 Public Health Surveillance: Questions and Answers Box 4. billion (which was especially due to losses in the tourism and exports industries). The 1991 cholera PRIMARY, SECONDARY, AND TERTIARY epidemic in Peru involved a total loss of $770 mil- PREVENTION IN PUBLIC HEALTH lion, which was primarily from losses in the tourism Primary: Prevention of the development of disease or injury and seafood industries (Rodier 1998). in a susceptible or potentially susceptible population through specific measures, such as immunization Intra-national and international borders are inef- Secondary: Efforts to decrease the duration and severity of fective for containing diseases, so investment in disease/injury through early diagnosis and prompt surveillance and public health is a wise investment intervention for the country in which the epidemic is or might Tertiary: Efforts to limit mortality and the degree of be currently occurring, as well as the countries to disability and promote rehabilitation and which it might spread. The cholera epidemic in Peru restoration of function after disease/injury mentioned above eventually spread throughout much of Latin America. Smallpox is another example of a disease that spreads quickly. The cost of the munization coverage among school-age children that surveillance and public health programs to eradi- form the basis of a surveillance system of vaccina- cate smallpox was relatively small in comparison tion programs. Surveillance of reports from to the increasing dividends to all countries for be- health-care providers on cases of measles to assess ing able to eliminate mass immunization programs whether appropriate treatment has been rendered for this disease.4 The economic devastation from would be an example of surveillance at the second- the AIDS epidemic can serve as a warning of the ary prevention level. Finally, routine assessment of potential consequences of a more rapidly lethal hospital-based records for utilization of rehabilita- epidemic of hemorrhagic fever (including, for in- tive services for those cases with severe measles stance, the Ebola virus), plague, or cholera should would be an example of surveillance at the tertiary we fail to control epidemics of any of these entities prevention level. at the local level and should they become national, regional, or international epidemics. Antibiotic re- Why invest in surveillance? sistance is an emerging cross-border issue that With relatively small investments, public health pro- requires surveillance for effective control and pre- grams are very effective in reducing death, disease, vention (http://www.who.int/emc/ and disability. By investing in public health surveil- amr_interventions.htm). While it necessitates an lance the public health system is made more effective investment in laboratory systems, in the long term and efficient. For example, surveillance can lead to such an investment may be minimal compared with early detection of a local epidemic when its control the costs of treating antibiotic-resistance diseases is more effective and less costly in dollars expended on a large scale or from years of productive life lost and lives claimed. Apart from the health sector, epi- (YPLL). demics can be costly because of their impact on productivity as well as on other aspects of the Beyond its role in controlling devastating epidem- economy. For instance, the economic impact of the ics surveillance is important for the control and plague epidemic in India in 1994 was a loss of $1.7 prevention of endemic diseases that reduce produc- 4 This is also true of the cost in terms of disability-adjusted life years (DALYs). 6 tivity and can be costly to manage. Good surveil- is mandatory reporting by health providers or health- lance systems permit early identification of diseases care facilities. The list of conditions is determined such as TB and syphilis that can easily be cured with by each country and primarily includes communi- low-cost treatments, combined with other public cable diseases. Communicable diseases commonly health actions. Early detection of these communi- subject to mandatory reporting are: childhood vac- cable diseases decreases the amount of time an cine-preventable diseases such as polio, measles, infected person is able to transmit the disease to tetanus, and diphtheria; TB; hepatitis; meningitis; others thus preventing, and potentially eliminating, and leprosy. However, reporting of noncommuni- new cases. Treatment of chronic noncommunicable cable conditions—such as infant and maternal diseases (NCDs) such as heart disease and diabetes deaths, injuries—and occupational and environmen- and their sequelae is expensive, so their prevention tal diseases—such as pesticide poisoning—are often is far more cost-effective. Prevention and control of required, as well. International regulations currently these diseases requires surveillance of the behavioral require reporting the occurrence of three diseases risk factors (BRFs—such as smoking, physical in- to the WHO: plague, yellow fever, and cholera (WHO activity, and obesity) that lead to their development, 2001b). as well as actions to promote the desired changes and risk reductions. Surveillance may be performed on any element of the chain of causation that leads to a communicable While there are human and fiscal costs of epidemic or NCD. For example, elements of measles surveil- and endemic disease, there are also opportunity costs lance could involve routinely assessing how many associated with investing in public health programs. members of a community are vaccinated, how many It is essential that interventions be evaluated and cases of measles occur, how many cases occur among resources targeted so that their contribution, com- vaccinated individuals (called vaccine failure), and pared with other possible interventions, is optimized. costs associated with vaccination programs and Surveillance can provide useful information to iden- treatment of cases, among many others. tify populations at greatest risk where intervention may make the most contribution and to gauge the Behavioral risk factors are also a reasonable target effectiveness of intervention programs. For example, for surveillance. Prevention of deaths due to heart surveillance of behavioral risk factors for diseases disease, lung cancer, and stroke includes the pro- such as human immunodeficiency virus/acquired motion of abstinence from smoking, while sexually immune deficiency (HIV/AIDS) may identify grow- transmitted infections (STI) and AIDS prevention ing high-risk sexual behavior in targeted populations. involves the promotion of condom use. The preven- It may also provide information on whether pro- tion and early detection of some cancers also involves grams such as public education are leading to an changes in behavior (such as regular Pap smears increase in preventive behaviors over time. In the and mammograms, use of sun block, or smoking case of HIV/AIDS, this would include increased con- cessation). dom use or decreased needle sharing. The expanding scope of conditions and determinants What is the spectrum of outcomes of conditions amenable to surveillance is, however, amenable to surveillance? a cause for concern. The number of conditions and Most countries have promulgated by law or regula- determinants designated for surveillance must be re- tion a list of public health conditions for which there stricted to the human and financial resources available 7 Public Health Surveillance: Questions and Answers to adequately sustain the surveillance system, and to line of diseases is presented in the second column of conditions in which surveillance can effectively lead table 2. However, the expansion of the list of notifi- to prevention. There is no “magic number” of con- able diseases will depend on a country’s public health ditions that should be included. Rather, the resources priorities. In some countries (for example, countries available to manage the system effectively and to in Eastern Europe and Central Asia) NCDs may be a collect data of reasonable quality should determine greater priority, and therefore BRF surveillance may the number of conditions and determinants that are be more important to include in the second line. Once included. Priorities must be established (discussed the system is developed other diseases may be added. below under Setting Priorities). Notifiable diseases High-income countries have dozens of conditions (such as botulism and anthrax) often occur at very under surveillance. It is preferable to achieve a rea- low frequency, but because of their public health sonable level of accuracy, connection to control implications it is essential any cases be reported. programs, and sustainability before adding diseases. Although there is no “magic number," table 2 pre- Overambitious designation of conditions for surveil- sents a possible scheme for developing a surveillance lance stems from at least two sources. On the one system. The first column designates a minimal list hand the resources for doing surveillance well are of diseases for surveillance. (Note that all countries underestimated. On the other hand even if a condi- of the world now have at least some sort of rudi- tion, however grievous, is not preventable, mounting mentary system of surveillance for at least polio and a surveillance system is a way for governments to TB.) Diseases should be added as the system evolves respond, albeit ineffectually, to societal pressures for and resources become available. A suggested second action. Table 2. Scheme For Developing And Expanding A List For Mandatory Disease Reporting Minimal list Second line Third line Vaccine preventable: Vaccine preventable: Vaccine preventable: Polioa Diphtheria Rubella Measles Pertussis Chickenpox Tetanus Mumps Communicable: Communicable: Communicable: TB Meningitis Hepatitis Syphilis Nosocomial infections HIV/AIDS Gonorrhea/Urethritis Foodborne pathogens Internationally required: Non-communicable: Non-communicable: Cholera Infant death Behavioral risk factors Yellow fever Maternal death Plague Pesticide poisoning In endemic areas: In endemic areas: In endemic areas: Malaria Dengue-especially hemorrhagic Encephalitis Leprosy Ebola/hemorrhagic fevers Onchocerciasisa (river blindness) Rabies Dracunculiasisa (guinea worm) a Targeted for eradication 8 Table 3. Major surveillance methods Surveillance methods Comments Mandatory disease notificationa by health- • Require immediate public health response; or care providers or facilities • Recognizable solely by providers Reports by laboratories (reporting source) • Immediate public health response may or may not be needed • Laboratory test needed for recognition or to meet case definition • Laboratory test adds relevant information (such as Salmonella serotypes, antibiotic susceptibilities for TB and pneumococcus, cell type for cancer) • Back-up to clinician’s reporting Sentinel surveillance • Useful for collecting detailed information on a subset of cases • Designed so findings can be generalized to a specified population • Collect limited information to recognize the onset, termination and characteristics of a particular public health problem of limited duration (such as influenza) • Used when incidence of a condition is high (such as diarrheal diseases, acute respiratory infection [ARI]) Periodic or ongoing prevalence surveys • To assess prevalence trends over time (such as HIV seroprevalence surveys, BRF surveys) • Optimal if designed to be useful to state and local public health agencies • Generate hypotheses regarding risk factors • Evaluate the effectiveness of a public health or clinical intervention Vital records • Surveillance of births and deaths; trends in causes of death • Key for infant and maternal mortality surveillance • May be used alone for some analyses Secondary analysis of datasets collected • Places no additional burden on public health surveillance systems for other purposes • Care must be taken in analysis and interpretation • Immediate public health response are not needed • Assess the public health impact or monitor trends • Measure morbidity costs due to chronic or recurrent health events • Potential data sources include hospital discharges, billing, insurance, emergency room, school/work attendance, immunization registries, work-site injury and law enforcement records a These diseases vary from country to country, and even from state to state. Source: Adapted from WHO 1999a. What are the major surveillance methods? really using the information for action rather than merely collecting and mothballing data. Generally, Mandatory reports of certain diseases by the more severe the illness (such as meningitis) the clinicians or health-care providers or facilities more likely it is to be reported. Reports from pro- This is the traditional source of surveillance data. viders are routinely based on clinical diagnoses, Compliance with reporting requirements varies which are not usually based on the most sophisti- greatly and is dependent on the health-care provider’s cated diagnostic testing. Hence, cases are more likely perception of whether the public health agency is to be reported as hemorrhagic fevers (rather than a 9 Public Health Surveillance: Questions and Answers specific type of virus), or as suspected diagnoses, Periodic or ongoing prevalence surveys such as suspected rabies in the case of fatal encepha- A periodic survey of a representative sample of the litis following an animal bite. Nevertheless, such population can provide useful information on preva- reporting alerts the public health authorities to po- lence of behavioral risk factors, utilization of tential problems. preventive measures, occurrence of exposures, inju- ries, self-reported disease, and so on. The benefit of Reports by laboratories sampling is that information from a relatively small Laboratories are usually more compliant in report- group of respondents provides accurate estimates of ing disease than are health-care providers. the general population. A repeated survey can qualify Surveillance systems based on laboratory reporting as surveillance, as in the case of phone surveys of must balance the greater accuracy of the diagnosis seatbelt use, or school-based surveys of tobacco use with the sensitivity of the system for detecting a or other behaviors among students. Continuous sur- meaningful proportion of cases in the community. veys require greater resources, but provide In more developed countries and those with stron- time-linked information that is very useful in assess- ger systems clear lines of communication between ing the impact of events or particular interventions. regional referral and reference laboratories and those responsible for surveillance should be nurtured, since Vital records the number of samples submitted (such as for sus- Vital records of births and deaths are generally pected encephalitis) to the laboratory, as well as the underutilized as a surveillance source. These records number of confirmed cases are a dependable source can be used to estimate the magnitude of certain of information. Due to high costs, the volume of labo- diseases and injuries, describe distribution (such as ratory testing in low-income countries is low and by age or geography), track trends, set priorities, and therefore the usefulness of lab-based systems is lim- fulfill many other useful public health needs. How- ited. Diagnostic accuracy in developing-country ever, collection of information without analysis and laboratories is also a frequent problem. dissemination for use in prevention does not qualify as public health surveillance. The reduction of IMR Sentinel surveillance and MMR are two millennium development goals In sentinel surveillance a sample of reporters (such as (MDGs)—whose surveillance is carried out using clinicians, hospitals, and local laboratories) are desig- vital records, primarily. Effective surveillance of IMR nated as the reporting sources. Sentinel surveillance and MMR at the local level can lead to more appro- is effective where the goal is to estimate the magni- priate interventions for preventing such deaths. tude and trends of a disease, rather than to detect the Electronic systems for reporting vital records data earliest or all cases, which may not be within the do- are making this type of surveillance more timely and main of the sentinel reporter. By focusing on a specific effective. (See box 13, in appendix B.4, for more in- sample of reporters the surveillance system has a bet- formation.) ter chance of obtaining accurate and high quality information. Sentinel reporting is sufficiently sensi- Secondary analysis of datasets collected for tive to detect common diseases such as influenza or other purposes diarrheal diseases, but is generally ineffective for epi- Data are collected by nonpublic health agencies for demics that are localized and that must be identified a myriad of reasons. For example, local industries as early as possible, such as any of the hemorrhagic will collect data on absenteeism and even on the fevers, cholera, or vaccine-preventable diseases. causes for absenteeism. Departments of transporta- 10 tion may collect information on motor vehicle acci- mation that is never used, often because the goals dents and injuries. This information may then are not clearly articulated or are focused on more contribute to the overall surveillance system. specific needs. What is the difference between surveillance What is the difference between vertical and and health information systems? integrated surveillance systems? Health information systems encompass all the dif- Vertical surveillance systems focus on one disease or ferent data collection systems available to a ministry injury. Information is then fed back into the specific of health (MoH), including information from hospi- disease control program. The information collected tals, clinics, and providers (such as the numbers of may be drawn from one or more elements in the patients, diagnoses, procedures, and outcomes; per- chain of causation and prevention of that disease or sonnel, and pharmaceutical and other procurement injury. For example, because of the current global systems; program-specific data such as vaccinations, effort to eradicate polio, information from surveil- prenatal care, disease treatment outcomes; and so lance systems is fed directly back to the Expanded on). Public health surveillance is one component of Program on Immunization (EPI) polio program, the health information system. Health information which mounts a rapid response when a case of acute systems everywhere, but particularly in low-income flaccid paralysis (AFP) is detected. Such surveillance countries, should avoid collecting too much infor- systems tend to be costly but very effective. In the FIGURE 1 INTEGRATED APPROACH TO COMMUNICABLE DISEASE SURVEILLANCE Source: WHO 2002. 11 Public Health Surveillance: Questions and Answers case of polio the costs are often borne by interna- an active search for persons who have had sexual tional donors who are supporting the global contact with infected persons to ensure their treat- campaign to eradicate the disease. ment. Little surveillance takes place in low- and middle-income countries because it is resource-in- In contrast, an integrated approach envisages a com- tensive; exceptions may include case finding in mon system for multiple diseases using similar outbreaks and contact investigation for STIs or TB. structure, processes, and personnel. (Figure 1) This requires coordination but is more efficient and less What are important issues when costly, because it allows building on existing re- considering sources for surveillance data? sources and capacity. It also promotes the most There are three major issues in considering alter- effective use of health resources. The WHO is cur- native sources of surveillance data. One issue is cost. rently recommending the creation of units at the Surveillance systems that are based on, or that national level to coordinate various surveillance ac- piggyback on, existing systems are less costly. Such tivities in communicable diseases. Coordination systems are also more likely to survive through the implies providing individual programs (such as pro- worst of times, since the rationale for maintaining grams for TB, vaccines, and injury prevention) with the program on which surveillance is based may the needed information. An integrated surveillance be more compelling to decisionmakers than sup- system collects information on behaviors related to porting a surveillance system that stands alone. For both NCDs and communicable diseases (condom use example, reporting of communicable diseases by for HIV, hand-washing practices for diarrheal dis- health-care workers is a low cost surveillance sys- eases, and hepatitis, for instance) tem. and—ideally—requires an integrated approach (WHO 2000). At the local level, integrated systems A second issue in selection of source of surveillance are often the norm and make particular sense since data is sustainability. Whether a surveillance sys- the numbers of cases for any particular disease may tem can be sustained and maintain its effectiveness be small and would not warrant separate vertical over time depends on many factors, including the systems. At the local level, the same personnel usu- complexity of the system, its burden on reporters, ally report and investigate all notifiable diseases. the reporters’ perception of the system’s value to them, the cost of the system, and program funders’ What is active versus passive surveillance? assessments of the system’s contributions to pre- Passive surveillance depends on voluntary data re- vention. ports from health-care providers, laboratories, and others. This is fundamental to any surveillance sys- The third major factor is whether the system meets tem. Active surveillance takes surveillance another its goals. There are numerous goals for surveillance, step and involves searching for cases by a surveil- including the detection of epidemics, responding to lance authority. House-to-house searches in health problems with appropriate public health ac- outbreaks, such as an outbreak of Ebola, is an ex- tions, and estimating the magnitude of a health ample of active surveillance. STI surveillance problem over time. The goals of each surveillance (gonorrhea or syphilis, among others) is often ac- system should be well specified. While not every sur- tive surveillance, with follow-up of cases confirmed veillance system meets all the goals of surveillance, by the laboratory to ensure all cases have been ad- a surveillance system that does not meet its speci- equately treated. STI surveillance usually involves fied goals should be corrected or abandoned. 12 What are the considerations in planning developing effective prevention and control pro- public health surveillance? grams, and evaluating interventions. Not every Setting priorities surveillance project can meet each goal, but a given Priorities must be set among the long list of diseases system must meet the goals for which it was de- and injuries that affect humankind. A common prob- signed. Data must be collected for a purpose, not lem is an over-ambitious approach in establishing just routinely, or the system will ossify, and partici- the list of notifiable diseases and injuries. The list of pants—especially reporters—will lose interest. associated risk and preventive factors is also long. Priorities should be based on public health impor- Case definition tance, including the measure of the disease’s The definition of what constitutes a “case” in terms seriousness for the individual, its current burden on of surveillance can depend on clinical diagnosis, society, the potential burden on society (which in- laboratory results, demographic information, or any volves the issue of communicability and the potential other agreed on attribute. Cases can be defined with for epidemic spread), and preventability. Priorities different degrees of certainty. For example, measles are also determined by the country’s capacity to re- may be defined by clinical presentation, or by so- spond with the necessary public health actions for phisticated laboratory procedures. Case definitions disease prevention and control. Middle-income coun- for surveillance must be standardized. They may be tries will be able to address an expanded list of health more or less restrictive than criteria used for clini- priorities compared with low-income countries. cal diagnosis (CDC 2001). Case definitions vary from country to country depending on what resources Parameters for measuring the importance of a health (particularly laboratory resources) are available event—and therefore the need for a surveillance sys- (CDC 1997). (See appendix A.8 for examples of WHO tem with which to monitor it—include: case definitions.) • Total number of cases, incidence, and prevalence Suspected versus confirmed cases It is important to maintain a high degree of suspi- • Indices of severity, such as the case-fatality cion and cast a wide net initially, in order not to miss ratio cases. Thus a definition for a suspected case is es- • Mortality rate tablished and the case is then confirmed through laboratory testing or clinical follow-up. Most sus- • An index of lost productivity: such as bed- pected cases are reported with minimal information; disability days this is followed up with a more thorough investiga- • An index of premature mortality: such asYPLL tion to confirm the disease, and assess potential sources and possible contacts so that they, too, may • Cost-effectiveness of interventions receive treatment, as needed. • Preventability • Epidemic potential What conditions lend themselves to successful surveillance programs? Setting goals and objectives As stated earlier, an important component of a na- There are many goals for surveillance programs. tional surveillance plan is a list of priority diseases These goals include estimating incidence, measur- for surveillance. This list, as short as possible, should ing trends, identifying cases for intervention, be established with the close participation of national 13 Public Health Surveillance: Questions and Answers health authorities. These questions should be ad- What data should be collected? dressed not only from the national perspective but Data sources and surveillance methods must be care- also from a regional, and possibly international, fully selected to match the specified goals of surveillance viewpoint because diseases may spread rapidly, with- and to maximize the attributes (such as timeliness, out regard for national boundaries. The questions sensitivity, positive predictive value, simplicity, or flex- in box 5 can be used to guide disease selection. ibility5—see also appendix A.6) of greatest importance at each level of the public health system for each In addition to specific diseases, specific syndromes health event or determinant (Romaguera, German, (including hemorrhagic fever syndrome) as well as and Klaucke 2001; CDC 2001). Data that are not some specific public health issues (such as antibi- needed should not be collected, unless it is more effi- otic susceptibility of some infectious agents) should cient to collect a standard set of easily available data be considered for surveillance. Following, or possi- for a group of health events. For example, it may be bly preceding, the list of priority diseases, an more convenient to collect a copy of a hospital ad- inventory of existing surveillance activities should mission sheet and abstract the desired information be carried out. This should be based on thorough later, rather than collect only the information needed on-site visits and a review of all key components of for surveillance while at the hospital. the health system, including public and private sec- tors where appropriate, as well as a review of any Surveillance systems vary in their need for person- nongovernmental organizations (NGOs) involved in ally identified information. Where there is a need to long-term health activities in the country. refer to the individual case or to identify the com- munity of the case, or perhaps the eating establishment frequented by the case, there is a need Box 5. for personal identifiers. At the national level, where attention is more focused on magnitude and trends CRITERIA FOR DISEASE SELECTION of conditions, personal identifiers are rarely needed. • Does the disease have a high disease impact (morbidity, disability, or mortality)? For some illnesses (such as meningitis, rabies, or gon- • Does it have a significant epidemic potential (including orrhea) it is necessary to collect the name of the cholera, meningitis, or measles)? patient, and the time and place of infection. In each • Is it a specific target of a national, regional, or instance direct individual actions are taken in re- international control program (by, for example, sponse to the case—whether the action is antibiotic the WHO, or other international or regional control prophylaxis, vaccination, or treatment of recent sexual programs)? contacts. However, for conditions such as dengue fe- • Will the information collected lead to significant public health action (such as an immunization campaign, ver there are no such direct, individual interventions, other specific control measures, or international but rather community level interventions. Therefore reporting)? simply counting case numbers is generally sufficient Source: WHO 1999a. and does not overburden the system. 5 Timeliness: delay between steps in the surveillance process. Sensitivity: identification of all cases of a disease or condition in question. Predictive value positive: the probability that a person with a positive test result actually has the disease. Simplicity: system structure and ease of operation. Flexibility: the ability of the system to adapt to changing needs, such as the addition of new conditions or data-collection elements. 14 Data should be collected in the least labor-intensive data are being sought and to what end—and to select manner possible consistent with the quality, scope, and the simplest system that allows for collection of these detail needed. An efficient surveillance system is one data. As the complexity of the surveillance system in which the minimum necessary local or state pub- increases, so does the cost of the system, as well as lic health resources (personnel and fiscal) are the infrastructure required (much more overhead is expended to collect information. involved in HIV sequencing in the laboratory than is involved in doing blood smears for malaria in the Are there stages of development in a public field). health surveillance system? Public health surveillance systems range in complex- Nearly all countries now have some type of surveil- ity from the very basic (using pins in maps to track lance for polio and TB, albeit with varying degrees cases) to the very complex (using digital GISs to link of success. Many countries have also developed sur- data and geography). Some involve very simple labo- veillance systems for measles, malaria, and cholera. ratory techniques (blood smears for malaria), while These systems may then form the basis for function- others are exceedingly sophisticated (HIV sequenc- ing public health surveillance systems. ing, which requires DNA testing). Data management can range from a box of index cards to enormous Table 4 offers considerations for implementing or datasets maintained on computers. strengthening surveillance systems in countries with weak institutional capacity and financial resources For all systems, however, there is a need to first iden- (which would include many African countries), and tify the goal or goals of the surveillance system—what for countries with moderate institutional capacity TABLE 4 FEASIBLE SURVEILLANCE SYSTEM CHARACTERISTICS RELATIVE TO DIFFERENT RESOURCE LEVELS Consideration Low resources Moderate resources Goals of Information for action but limited to highest priority Same but extended scope of conditions and routine surveillance diseases and outbreaks of most serious communicable use for health planning and evaluation. diseases. Strive to use surveillance data for planning. Scope of Vital registration; core communicable diseases; detection Same plus expanded list of communicable and NCDs; surveillance of outbreaks and preventive interventions (seat belt use). surveillance for BRFs (smoking) Training needs Basic concepts of surveillance applied to routine Application of more complex methodology for disease control and outbreak investigation. surveillance of NCDs, injuries, and so on. Information Reliance on routine means of communication: Use of e-mail, Internet sites, and so on if available in- transfer mail, phone, or fax. country (usually a mix of old and new). Laboratory Emphasis on accurate basic capability; reliance on More capability in-country with reference laboratories reference laboratories for sample analysis. used more for quality control than for sample analysis. Communication Focus on direct communication with disease reporters Expanded range of communication of information to insure transmittal of information to those who must to broader audience with goal of raising societal know and on whom the surveillance system relies public health competency. for routine information. Major problems Ineffective surveillance (too many conditions, Enthusiasm based on series of successes leading to in- too much useless information, too little connection creasing expectations that are not matched by new to action) leading to decreased interest in surveillance resources; greater emphasis on chronic diseases where and public health. success of public health intervention is less demonstrable in the short term. 15 Public Health Surveillance: Questions and Answers and financial resources (including most Latin Ameri- priate for the country. Historically, effective surveil- can or Eastern European countries). lance systems have used very basic means of communications, such as postcards. Development of surveillance builds on success. Dem- onstration of the effectiveness of an initial In designing the surveillance system consideration surveillance system builds support among reporters should first be given to development of the analysis and those who must provide resources. It can create plan. What data should be analyzed for the intended public awareness of the importance of information audience? Analysis can have different levels of com- for managing epidemics, tracking diseases, and bet- plexity, depending on technical capacity and needs ter health in general. Once the potential benefits of for decisionmaking. Decisions must be made con- surveillance is better understood it may be difficult cerning the frequency of tabulation and the level of to initiate a surveillance system for a small, limited analysis (for instance local as opposed to state, or array of conditions. However, being too ambitious state as opposed to national). Very basic tabulation initially may lead to loss of enthusiasm for any con- of data is often quite useful for disease-prevention tinued effort and be more destructive than starting activities. More complex analyses sometimes reveal slowly. opportunities for prevention that are lost in the sim- plest data analyses. The degree of effectiveness of data While advances in computer and information tech- analysis is more dependent on an analysis that is logi- nology present many opportunities for improved cal in thinking and committed to prevention, and less surveillance, they also present new threats to the de- based on an automated or regimented approach. velopment of effective surveillance. It is easier to buy equipment (provided funding is available) than to What are the common issues in train and develop adequate staff and to build part- communication of surveillance results? nerships with disease reporters and others, without Communication to whom? whom surveillance would not function. Effective sur- The communication style and format will depend veillance can be accomplished with rudimentary on the intended audience. It may be directed to the technology; technology will not replace conceptual un- governmental hierarchy, including local, state, and derstanding, management skills, and development of national authorities, or communication may flow essential partnerships. across parallel levels of government, such as village- to-village or state-to-state. There may be a need to What systems are used for data transmittal? communicate internationally among governments. The data transmission system should be the result Obviously, information to individuals who must of design choices that are practical and feasible for make personal decisions (concerning condom use, the situation. There is an array of potential report- for instance) must be clearly articulated. Another ers to be considered, including providers, clinics, frequently used avenue of communication is to hospitals, and community health workers. In addi- nonhealth organizations or NGOs that may play a tion, many potential communications media may be role in prevention (this category includes schools, employed, including postcards, telegraph, tele- industry, and the media). phones, faxes, e-mail, and the Internet. Similarly, databases may be based on paper files, may be com- Means of communication? puterized, or may be Internet-based. The methods Among the many potential vehicles for communi- of data transmittal must be technologically appro- cating to the parties identified above are: 16 • What is the relationship between Yearly bulletins (yearly reports of vital statistics) laboratories and surveillance? • Periodic reports of notifiable diseases (such Laboratories play many critical roles in prevention as weekly reports of numbers of notifiable and are essential partners in surveillance. Clinical cases, reports of epidemics, and other events) diagnosis often requires laboratory confirmation, • Periodic reports of epidemics of local, re- such as in the diagnosis of malaria or TB. Labora- gional, national, or international importance tory work also determines, through drug • Newsletters and mailings to professional susceptibility testing, how best to treat a patient for groups TB or dysentery. Beyond clinical diagnosis for the individual, specialized laboratory testing may dem- • Press and media releases onstrate that a common organism is the cause of • Interviews with the press multiple outbreaks that are separated in space and time. Research laboratories may identify the cause • Posting to Web sites for a heretofore-unknown condition, such as was the case with Legionnaire’s disease and mad cow dis- Problems in communication? ease soon after their clinical recognition. Public health practitioners often run into attitudi- nal problems among potential data users and A complete health-care system will have a continuum collectors. Among the more important problems are: of laboratories at the local, state, national, and in- • Incredulity that communication can lead to ternational levels that work together in a cohesive change network. The laboratory continuum is characterized • Potential inconsistency of public health and by its diagnostic and research capability, and by its political messages capability for containment of infection. A system of grading laboratories for biosafety has been devel- • Overly hierarchical, top-down communication oped: gradations range from P1 to P4, with P1 • Secretive attitudes requiring the least and P4 requiring the most biosafety measures (CDC/NIH 1999). The P4 labo- Problems in preparation? ratories, however, are exceedingly costly to build and Potential pitfalls in successfully preparing informa- maintain and, to date, exist only in a small number tion include the following: of countries. • Communication of data rather than commu- nication of a public health message It is important for each system to consist of a con- • Undisciplined or impromptu policy developed tinuum of laboratories providing the most basic to ad hoc during communication itself the most sophisticated services, but it is implausible that resources are sufficient everywhere to provide • Lack of timeliness the entire continuum. Some smaller, low-income • Poor framing of message countries may need to consider cross-border collabo- ration and regional reference laboratories to resolve • Inconsistent messages that are not integrated some of their laboratory needs. However, such col- into overall public health strategy laboration still requires an organized system of • Over-dependence on only one of many effec- transporting specimens and communicating results tive communication strategies in order to be successful. While sophisticated equip- 17 Public Health Surveillance: Questions and Answers ment must be reserved for the most sophisticated What are the components of an effective referral laboratories, good laboratory practices— surveillance program? such as the use of gloves and avoidance of procedures Surveillance systems can either show their public that aerosolize specimens—should be practiced uni- health merit (and become more effective), or they versally. Good laboratory practices are the first line can spiral downward. Malison has described this of defense against inadvertent infection of labora- downward spiral and presents a model for under- tory workers and the community. standing how ineffective surveillance systems evolve (Malison 1992). Poor quality data is not useful, so it How do you evaluate the surveillance is not in demand by those who would effectively system? improve the public health. Other demands for data Evaluation of an existing surveillance system can be continue from "archivists," who are interested more broken down into the following essential steps. Com- in process and completeness of data than in their plete details of the process may be found in utility (see table 5). Lack of demand reduces incen- appendixes A.6 and B.1. tives to improve quality, so the system deteriorates. • What are the goals and objectives of the sur- The cycle continues until the supply of data—which veillance system, and is it meeting them? continue to worsen in quality—equals demand that comes less from public health decisionmakers inter- • What is the public health importance of ested in improving outcomes and more from the diseases or health events under surveil- "archivists" interested in bean counting. lance? • How does the system operate? What are the issues of data privacy and • What resources are required? accessibility for use? Surveillance systems and the information systems that • What are the system’s attributes (see appen- support them should be designed in such a manner dix A.6)? Is the system communicating with that personal identifying information is accessible only data sources? to public health professionals who need to collect ad- ditional information of importance required to • Is there communication and feedback be- intervene to prevent adverse public health outcomes tween the different administrative levels? (such as transmission of communicable diseases, • Does the system provide useful information? preventable workplace injuries, or progression from Is it leading to public health action? mild to advanced chronic disease), or for bona fide research. Indiscriminant data access can be mini- • Are the findings provided to, and used by, mized by providing training on confidentiality and policymakers? privacy to surveillance staff, providing privacy on There must be support from all those on whom the work phones, locking cabinets for hard copy data surveillance system depends. These groups who ini- storage, secure computer storage for electronic data, tiate and sustain the system includes government and limiting transmission of data over public com- officials, health-care providers, community health munication lines. It should be emphasized that workers, NGOs, and advocacy groups. Starting sur- confidentiality is both a matter of hardening data veillance for a disease or BRF that is not sustainable storage from intrusion, as well as limiting gossip and due to a lack of resources is counter-productive in inadvertent disclosure of personal information. the long run. 18 TABLE 5 FACTORS LEADING TO USEFULNESS OR INEFFECTIVENESS OF SURVEILLANCE SYSTEMS Factor or element Effective system Ineffective system Number of conditions Fewer Too many Amount of information per case Lean Too much Burden on reporter ( reporting forms) Lean Too complex and burdensome Decisionmakers’ interest in surveillance data High Low Goals for surveillance Clear and supported May never have been clear Reporting strategy for serious but Enough information to meet Complete reporting common conditions goals and make decisions Usefulness of data to local collectors High Low Limited to analysis of data and archiving Low High Usefulness to decisionmakers for High Low prevention action Inadvertent disclosure of personal information may tive mandatory notification to be implemented. Sur- occur for various technical reasons, such as occur veillance and disease-control activities are authorized when mapping cases with geographic information in state statutes as part of the "police powers" of systems (GIS) to the point where an individual is states. These laws usually include restrictions on the identifiable. use and accessibility of the information thus trying to balance the needs of society to protect the public’s In many cases personal identifiers (such as names, health, with protection of the individual’s right to addresses, and social security numbers) are not privacy (Matthews, Neslun, and Churchill 2000). needed to conduct effective surveillance. For ex- ample, there is generally no need for personally How are outbreaks recognized? identifiable data at the national level, where public Epidemics come in various sizes, from smaller, lo- health issues mainly involve magnitude and trends. calized outbreaks (such as plague, food-poisoning, typhoid, diphtheria, Ebola), to widespread Is a legal basis for public health surveillance pandemics (cholera in South America in 1992–94, necessary? influenza worldwide in 1918, and the current almost- Medical information obtained by physicians and worldwide pandemic of HIV). Recognition of other health-care providers is usually considered outbreaks occurs in various ways. confidential. However, mandatory reporting of some diseases includes personal identifiers such as name Localized outbreaks are usually identified and re- and address of the person affected. This permits the ported by an astute observer: by a victim, health case investigation needed to control communicable department, or health practitioner. This is an infor- diseases or the identification of interventions to pre- mal system that works well when public health vent further cases from occurring as in infant and officials are flexible, curious, receptive to phone calls, maternal mortality surveillance. In part due to this and responsive. It is likely that some reports will be conflict between individual rights and societal needs, false positives. Nonetheless, officials should remain a legal basis is required in most countries for effec- responsive to each of these reports. 19 Public Health Surveillance: Questions and Answers In contrast, formal systems for detection of epidem- which allows linkage of otherwise independent out- ics, such as those in place for pneumonia and breaks. A recent example of the utility of this influenza surveillance, depend on systematic col- technique was the recognition of transmission of lection and analysis of data and comparison with multidrug-resistant TB among the inmates of New the expected number of cases. Many local and state York state prison facilities (CDC 1991). health departments in the Americas maintain "en- demic channels" for diseases (such as malaria and How do I complete the surveillance dengue fever) that are based on observations from process? the previous five years. A range for the maximum The surveillance process is completed when action number of cases expected over the period of a year is taken. Possible actions range from disease con- is developed. When the number of cases exceeds trol measures to policy and planning or resource the maximum expected—the epidemic threshold— allocation activities. an epidemic is considered to be occurring, and public health actions beyond the routine should be initiated. Recent advances in laboratory techniques have im- THE #1 TAKE-HOME MESSAGE proved public health practitioners’ abilities to There is no value to a surveillance system unless the information recognize and track epidemics. Among these tech- is used for actions that prevent or control diseases. niques is genetic fingerprinting of disease organisms, 20 APPENDIX A.1 What Software Is Available for Surveillance? T here are numerous software packages available for use in public health surveillance. Many of them are complex and are aimed primarily at sta- for their use, may be found at http://www.cdc.gov/ epiinfo. tistical analyses of datasets. Several easy-to-use Prophet software packages are widely accepted in the sur- Prophet offers advanced, easy-to-use software tools veillance community. for data management, visualization, and statistical analysis. Information concerning this package may Epi-Info be found at www.prophet.bbn.com. Epi-Info and Epi-Map (Centers for Disease Con- trol and Prevention) are public domain software GIDEON packages designed for the global community of GIDEON, created by C.Y. Informatics, is an interac- public health practitioners and researchers. Both tive computer program for diagnosis and reference provide easy form and database construction, data in the fields of tropical and infectious diseases, epi- entry, and analysis with epidemiologic statistics, demiology, microbiology, and antimicrobial maps, and graphs. A Web site devoted to the dis- chemotherapy. Information concerning this package semination of these softwares, including tutorials may be found at http://www.cyinfo.com. 21 22 APPENDIX A.2 What Are International Sources of Surveillance Information? I ncreasingly, information on surveillance may be accessed electronically. Several of the more im- portant resources are listed below. • Search for and retrieve MMWR articles and prevention guidelines published by CDC. • Query dozens of CDC datasets via “fill-in-the blank” request screens. Public-use datasets World Health Organization about mortality, cancer incidence, hospital The WHO maintains a wealth of information about discharges, AIDS, BRFs, diabetes, and many international public health concerns. Useful items other topics are available for query, and the for a Task Manager include a series of basic docu- requested data can be readily summarized and ments outlining WHO policy, disease outbreak news, analyzed. and the WHO Statistical Information System, which contains the data from the WHO’s mortality data- • Locate the name and e-mail addresses of CDC base on causes of death, causes of infant death, life staff and registered CDC WONDER users. expectancy, and age-standardized death rates; sta- • Post notices, general announcements, data tistical information on basic health indicators, files, or software programs of interest to pub- burden of disease, health personnel, international lic health professionals in an electronic forum, classifications, HIV/AIDS, United Nations popula- for perusal by CDC staff and other CDC WON- tion data, links to national health-related Web sites, DER users. member states of the WHO, and links to other sources of health information. This information may 2. WISQARSTM be accessed at: www.who.int. WISQARSTM (Web-based Injury Statistics Query and Reporting System), pronounced “whiskers,” is an Centers for Disease Control and Prevention interactive system that provides injury-related mor- CDC maintains a number of electronic databases that tality data useful for research and for making are easily accessible. CDC databases may be accessed informed public health decisions. The user can use at www.cdc.gov/scientific.html “injury mortality reports” to determine injury deaths and death rates for specific external causes of inju- 1. CDC WONDER ries. The user can also use “leading causes of death CDC WONDER is an easy-to-use system that provides reports” to determine the number of injury-related a single point of access to a wide variety of CDC re- deaths relative to the number of other leading ports, guidelines, and U.S. public health data. CDC causes of death in the United States or in individual WONDER (http://wonder.cdc.gov/) allows the user to: states. 23 APPENDIX B.1 EVALUATION OF THE SYSTEM AND CAPACITY 3. Behavioral Risk Factor Surveillance System ProMED-mail In 1984 CDC established the Behavioral Risk Fac- The ProMED-mail electronic outbreak reporting sys- tor Surveillance System (BRFSS) to develop and tem, sponsored by the International Society for conduct surveys to monitor state-level prevalence Infectious Diseases, was inaugurated on the Internet of the major behavioral risks among adults associ- in August 1994 to monitor emerging infectious dis- ated with premature morbidity and mortality (such eases on a global basis. It is the only rapid reporting BRFs include smoking, exercise, and seat-belt us- system of outbreaks open to all sources and free of age). The premise was to collect data on actual political restraints. Expert moderators screen all re- behaviors, rather than on attitudes or knowledge, ports before posting. that would be especially useful for planning, initi- ating, supporting, and evaluating health promotion A central goal of ProMED-mail is to establish a di- and disease prevention programs. The BRFSS, ad- rect partnership among scientists and doctors in all ministered and supported by the Division of Adult parts of the world by making it possible for all to and Community Health, National Center for share information and discuss emerging disease con- Chronic Disease Prevention and Health Promotion cerns on a timely basis. ProMED-mail welcomes the (a division of the CDC) is an ongoing data collec- participation of all interested colleagues, students, tion program. State-specific data on various BRFs and interested people outside the health and bio- are retrievable. medical professions. There is no charge for subscribing. Additional information may be found at www.promedmail.org/pls/promed/promed.home. 24 APPENDIX A.3 What Global and Regional Alert Systems Exist? T he WHO publishes notices of outbreaks on their Web site: www.who.int/disease-outbreak-news/ index.html. In addition, CDC publishes the Morbidity and Mor- tality Weekly Report (MMWR), which features topical reports of epidemics, surveillance data, and other public health concerns (www.cdc.gov/mmwr). Pro-MED is the most timely source for reports of epidemics (www.promedmail.org/pls/promed/ promed.home). 25 26 APPENDIX A.4 What Training Is Available? T raining needs will vary according to the particu lar circumstance. For instance, World Bank Task Managers have different needs from, say, sanitation Training Programs in Epidemiology and Public Health Intervention Network, Inc. In June 1997, the Training Programs in Epidemiol- specialists. In general, anyone involved in public ogy and Public Health Intervention Network, Inc. health surveillance should have some insight into the (TEPHINET) was founded in a meeting in Annécy, basics of epidemiology and the purposes of surveil- France, attended by directors of 17 national and re- lance. The CDC, universities, and—increasingly—the gional training programs, in response to an invitation Internet are among the venues that provide oppor- of the WHO’s Division of Communicable Disease tunities for training. Several of these venues are Surveillance and Response; CDC; the Foundation discussed below. Mérieux; and the national programs that have pro- vided continued support to TEPHINET. Field Epidemiology Training Programs For nearly 20 years CDC’s international health spe- TEPHINET programs share a practical field-based cialists have collaborated with ministries of health or “learning-by-doing” approach to public health around the world to establish and conduct Field Epi- training. They are affiliated with governmental in- demiology Training Programs (FETPs) for specialists stitutions, such as ministries of health, national in epidemiology. These programs are modeled on the disease prevention and control programs, and aca- Epidemic Intelligence Service, CDC’s primary applied demic institutions. Emphasis is placed on developing epidemiology training program. The two-year train- competencies in the epidemiologic process, commu- ing and service programs are designed for health nication in public health, professional skills, and professionals in entry- or mid-level positions, and are other core public health sciences. For further infor- intended to assist in building capacity in applied epi- mation, consult http://asclepius.ic.gc.ca/tephinet. demiology and enhanced public health practice. Public Health Training Network Countries with FETPs include: Australia, Brazil, The Public Health Training Network (PHTN) of CDC Canada, the countries in Central America, Colom- is a distance learning system that takes training to bia, the Arab Republic of Egypt, Germany, Indonesia, the learner. PHTN uses a variety of instructional Italy, Japan, Jordan, Mexico, Peru, the Philippines, media ranging from print to videotape and multi- Saudi Arabia, Spain, Taiwan (China), Thailand, and media in order to meet the training needs of the the United States. For further information consult public health work force nationwide. Since 1993 www.cdc.gov/epo/dih/fetp.html. PHTN has delivered nearly 1 million training oppor- 27 APPENDIX A.4 WHAT TRAINING IS AVAILABLE? tunities to professionals in public health settings and, was developed for use in the United States, but is in increasingly, in health care and related settings. For the public domain and can be adapted for use in further information consult www.cdc.gov/phtn/ other countries. “Surveillance in a Suitcase” is avail- whatis.htm. able free of charge at: http://www.cdc.gov/epo/ surveillancein/. “Surveillance in a Suitcase” “Surveillance in a Suitcase” is a training manual Academic Opportunities developed by CDC that follows the book Principles Numerous universities offer courses in public and Practice of Public Health Surveillance, edited by health surveillance. These include, but are not lim- Steven M. Teutsch and R. Elliott Churchill (Teutsch ited to: and Churchill 1994). Staff at the CDC wrote each of • Washington University (http:// the 13 chapters in “Surveillance in a Suitcase.” The depts.washington.edu/hsic/subject/ text provides a practical and up-to-date reference on subjects.html) the topic of public health surveillance and is the ba- • Emory School of Public Health sis of this training manual. (www.sph.emory.edu/home.html) There are 14 lessons in the training package. Each • Johns Hopkins School of Public Health lesson consists of a lecture outline and appropriate (www.jhsph.edu) overheads that follow the narrative. Two work exer- • Harvard School of Public Health cises dealing with public health surveillance and (www.hsph.harvard.edu) other practical exercises are included. This manual is to be used for teaching public health surveillance • London School of Hygiene and Tropical Medi- to public health and other health professionals. It cine (http://www.lshtm.ac.uk/) 28 APPENDIX A.5 Where Can I Find Useful Textbooks and Articles on Surveillance? R ecommended texts include Teutsch and Churchill 2000b; and Halperin, Baker, and Monson 1992 (See references). www.who.int/emc/surveill/index.html—Integrated Disease Surveillance. Other sources The Internet has become an enormous repository of www.who.int/emc/ surveill/index.html valuable information on public health surveillance. www.cdc.gov/preview/mmrwhtml/rr5013a1.htm Useful information and articles include the following: w w w. p h . u c l a . e d u / e p i / s n o w / www.who.int/emc-documents/surveillance/ broadstreetpump.html—A fascinating historical whocdscsrisr992c.html look at Dr. John Snow (1813–58), a legendary fig- http://www.who.int/emc/amr_interventions.htm ure in the history of public health, epidemiology, and anesthesiology. Additional readings w w. c d c . g o v / m m w r / p r e v i e w / m m w r h t m l / Aylward, R. B., H. F. Hull, S. L. Cochi, R. W. Sutter, 00042730.htm—A historical overview of CDC; na- J. M. Olive, and B. Melgaard. 2000. “Disease tional morbidity data from June 8, 1946, and June Eradication as a Public Health Strategy: A Case 22, 1996; reprints of articles published in CDC’s Study of Poliomyelitis Eradication.” Bull WHO “earlier years” reports about an outbreak of small- 78: 285–97. pox and an outbreak of pentachlorophenol CDC (Centers for Disease Control and Prevention). poisoning in newborn infants; and information 1991. “Transmission of Multidrug-Resistant resources about CDC. Tuberculosis among Immunocompromised Per- sons in a Correctional System.” MMWR 41 (28): www.who.int/aboutwho/en/history.htm—A brief 507–09. history of the WHO. ———. 1993. “Recommendations of the Interna- www.who.int/emc-documents/surveillance/ tional Task Force for Disease Eradication.” whocdscsrisr20012c.html—Protocol for the As- MMWR 1993; 42 (RR-16): 1-38. sessment of National Communicable Disease Dowdle, W. R., and D. R. Hopkins, eds. “The Eradi- Surveillance and Response Systems: Guidelines cation of Infectious Diseases.” Dahlem workshop for Assessment Teams. report. John Wiley & Sons Ltd, Chichester, En- www.who.int/emc-documents/surveillance/ gland, 1998. whoemcdis972c.html—Protocol for the Evalua- Hennekens CH and Buring JE. Epidemiology in Medi- tion of Epidemiological Surveillance Systems. cine. Little. Brown and Company. Boston. 1987. 29 A NNEX V: B UDGET I TEMS FOR P UBLIC C OMMUNICATION P ROGRAM TO S UPPORT P RIVATIZATION Last, J. M. A Dictionary of Epidemiology. 2nd edition. White, M. E., and S. M. McDonnel. 2000. “Public New York: Oxford University Press, 1988. Health Surveillance in Low- and Middle-Income PAHO (Pan American Health Organization). “Epi- Countries.” In Teutsch, S. M., and R. E. Churchill, demiologic Surveillance after Natural Disaster.” eds., Principles and Practice of Public Health Sur- Washington D.C. 1982. veillance. Second edition. Oxford University Press. Romaguera, R., with R. German, and D. Klaucke. Wilcox, L. S., and J. D. Marks, eds. 1994. “From Data 1993. “Evaluating Public Health Surveillance.” In to Action: CDC’s Public Health Surveillance for Teutsch, S. M., and R. E. Churchill, eds., Prin- Women, Infants, and Children.” USDHHS. ciples and Practice of Public Health Surveillance. New York: Oxford University Press. ALSO SEE REFERENCES AFTER PART B. 30 APPENDIX A.6 How Are Surveillance Systems Evaluated? T he evaluation of surveillance systems should promote the best use of public health resources by ensuring that only important problems are un- Outline of tasks for evaluating a surveillance system 1. Describe the public health importance of each der surveillance and that surveillance systems health event under surveillance. The following operate efficiently. Insofar as possible the evaluation are the three most important categories to of surveillance systems should include recommen- consider: dations for improving quality and efficiency—by • Total number of cases, incidence and preva- eliminating unnecessary duplication, for instance. lence Most important, an evaluation should assess whether • Indices of severity such as the mortality rate a system is serving a useful public health function and the case-fatality ratio and is meeting the system’s objectives. • Preventability Because surveillance systems vary widely in meth- 2. Describe the system to be evaluated odology, scope, and objectives, characteristics that • List the objectives of the system are important to one system may be less important to another. Efforts to improve certain attributes— • Describe the health event or events under sur- such as the ability of a system to detect a health event veillance. State the case definition for each (sensitivity)—may detract from other attributes, such health event. as simplicity or timeliness. Thus, the success of an individual surveillance system depends on the proper • Draw a flowchart of the system balance of characteristics, and the strength of an • Describe the components and operation of the evaluation depends on the ability of the evaluator to system assess these characteristics with respect to the system’s requirements. Any approach to evaluation • What is the population under surveillance? must be flexible, in order to accommodate these • What is the timeframe and time period of data objectives. With this in mind, the guidelines that fol- collection? low describe measures that can be applied to surveillance systems, with the understanding that all • What information is collected? measures will not be appropriate for all systems and • Who provides surveillance information? taking into account the time constraints and com- plexity of the process. • How is information transferred? 31 APPENDIX A.6 HOW ARE SURVEILLANCE SYSTEMS EVALUATED? • How is information stored? can be described in several ways. Health events that affect many people or require large expenditures of • Who analyzes the data? resources clearly have public health importance. • How are the data analyzed and how often? However, health events that affect relatively few per- sons may also be important, especially if the events • How often are reports disseminated? cluster in time and place—a limited outbreak of a • To whom are reports distributed? severe disease. At other times, public concerns may focus attention on a particular health event, creat- • How are reports distributed? ing or heightening the sense of importance. Diseases that are now rare because of successful control mea- 3. Indicate the level of usefulness by describing sures may be perceived as “unimportant,” but their actions taken because of data from the surveil- level of importance should be assessed in light of lance system. Characterize the entities that their potential to re-emerge. Finally, the public health have used the data to make decisions and take importance of a health event is influenced by its pre- actions. List other anticipated uses of the data. ventability. 4. Evaluate the system for each of the following Parameters for measuring the importance of a health attributes: event—and therefore the need for a surveillance sys- • Simplicity tem with which to monitor it—include: • Flexibility 1. Total number of cases, incidence, and preva- lence • Data quality 2. Indices of severity, such as the case-fatality • Acceptability ratio • Sensitivity 3. Mortality rate • Predictive value positive 4. An index of lost productivity: such as bed-dis- • Representativeness ability days • Timeliness 5. An index of premature mortality: such asYPLL • Stability 6. Cost-effectiveness of interventions 7. Preventability 5. Describe the resources needed to operate the system (that is, the direct costs). 8. Epidemic potential 6. List conclusions and recommendations. State These measures of importance do not take into ac- whether the system is meeting its objectives, count the effect of existing control measures. For and address the need to continue or modify the example, the number of cases of vaccine-preventable surveillance system, or both. illness has declined following the implementation of school immunization laws in the United States The public health importance of a health event and and elsewhere, and the public health importance of the need to have that health event under surveillance these diseases would be underestimated by case 32 counts alone. In such instances it may be possible to • Identify risk factors associated with disease estimate the number of cases that would be expected occurrence? in the absence of control programs. • Permit assessment of the effects of control measures? Assessing the usefulness of a surveillance system: An assessment of the usefulness of a surveillance sys- • Lead to improved clinical practice by the tem should begin with a review of the objectives of health-care providers who are the constituents the system and should consider the dependence of of the surveillance system? policy decisions and control measures on surveil- lance. Depending on the objectives of a particular A surveillance system is useful if it contributes to surveillance system, the system may be considered the prevention and control of adverse health events, useful if it satisfactorily addresses at least one of the including an improved understanding of the public following questions. health implications of such events. A surveillance Does the system: system can also be useful if it helps to determine • Detect trends signaling changes in the occur- that an adverse health event previously thought to rence of disease? be unimportant is actually important. • Detect epidemics? Not every surveillance system will meet all the goals • Provide estimates of the magnitude of mor- of surveillance. Inevitably tradeoffs have to be made bidity and mortality related to the health that involve resources; work force; infrastructure; problem under surveillance? and social or political constraints, or both. • Stimulate epidemiological research likely to lead to control or prevention? Source: CDC 2001; WHO 2001a. 33 34 APPENDIX A.7 What Are the Key Statistical Concepts for Surveillance? S tatistics and epidemiology form the cornerstone of public health surveillance. An understanding of statistical principles is necessary to comprehend Case-fatality rate is another incidence measure: Case-fatality rate = Number of deaths from the disease Total number of cases of the disease the published literature and practice in a rational manner. The purpose of this section is to review some Attack rate is also an incidence measure: of the basic statistical principles and formulas. More Attack rate = Number of cases of the disease in-depth discussion can be obtained in texts of epi- during a given time period demiology and biostatistics. Total population at risk due to having been exposed Measurements of disease frequency Prevalence is the most frequently used measure of Test result characteristics disease frequency and is defined as: It is important to understand predictive value, which Prevalence = Number of existing cases of a disease helps in interpreting test results for an individual. Total population at a given point in The predictive value positive expresses the probabil- time ity that a person with a positive test result is actually infected; the predictive value negative is the probabil- Incidence quantifies the number of new cases that ity that a person with a negative test result is not develop in a population at risk during a specific time infected. The predictive value depends not only on interval: the accuracy of the test itself but also on the preva- Cumulative Number of new cases of a disease lence (the percentage of persons who are infected in incidence = during a given time period the population tested). The predictive value of a posi- Total population at risk tive test result decreases as the prevalence declines in the population tested. Cumulative incidence reflects the probability that an individual will develop a disease during a given time Table 6 demonstrates how these values are generated. period. From this table four important statistics can be de- Mortality rate is an incidence measure: rived: Mortality = Number of deaths • Sensitivity—A sensitive test detects a high pro- Total population portion of the true cases, and this quality is measured by a / a + c. 35 APPENDIX A.7 WHAT ARE THE KEY STATISTICAL CONCEPTS FOR SURVEILLANCE? Table 6 Comparison of a survey test with a reference test Survey test result Reference test result Totals Positive Negative Positive True positives, False positives = (b) Total test positives = correctly identified = (a) (a + b) Negative False negatives = (c) True negatives Total test negatives = correctly identified = (d) (c +d) Totals Total true positives = Total true negatives = Grand total = (a + c) (b + d) (a + b + c + d) • Specificity—A specific test has few false posi- • Predictive value—The proportion of positive tives, and this quality is measured by d/b+ d. test results that are truly positive; it is impor- tant in screening. It should be noted that both • Systematic error—For epidemiological rates it systematic error and predictive value depend is particularly important for the test to give on the relative frequency of true positives and the right total count of cases. This is measured true negatives in the study sample (that is, on by the ratio of the total numbers positive to the prevalence of the disease or exposure that the survey and the reference tests, or (a + b) / is being measured). Predative value is mea- (a + c). sured by a/a+b. 36 APPENDIX A.8 How Does Surveillance Case Definition Relate to Sensitivity and Specificity? A s noted in part A above (discussion of surveil lance methods) public health officials rely on health-care providers, laboratory personnel, and that all possible cases are captured, even if many are false positive. other public health personnel to report the occur- The WHO has a catalog of case definitions for infec- rence of notifiable diseases, conditions, injuries, and tious diseases (WHO 1999a). so on to health departments. To facilitate this report- ing case definitions are developed to provide uniform Examples of case definitions from the WHO include: criteria for identifying these diseases and conditions. CHOLERA Case definitions always involve a balancing act of Clinical case definition sensitivity as opposed to specificity. A definition is • In an area where the disease is not known to be present: sensitive if it identifies all the cases of a disease or severe dehydration or death from acute watery diarrhea in a patient aged 5 years or more or condition in question. A definition is specific if it • In an area where there is a cholera epidemic: acute watery excludes individuals without the disease or condi- diarrhea, with or without vomiting in a patient aged 5 tion in question. Sensitivity and specificity thus years or more.6 describe the accuracy of the test. Sensitivity deter- Laboratory criteria for diagnosis mines the percentage of false-negative results, and • Isolation of Vibrio cholerae O1 or O139 from stools in any specificity determines the percentage of false-posi- patient with diarrhea. tive results, when a large number of positive and Case classification negative samples are tested. • Suspected: A case that meets the clinical case definition. • Probable: Not applicable. An insensitive case definition may suffice when cases • Probable: Not applicable. are plentiful and it does not matter if some cases are • Confirmed: A suspected case that is laboratory-confirmed. missed. On the other hand, in the end-game of con- Note: In a cholera-threatened area, when the number of trol (when a disease nears elimination), it is “confirmed” cases rises, shift should be made to using primarily important to have a sensitive definition to ensure the “suspected” case classification. 6 Cholera does appear in children under 5-years old; however, the inclusion of all cases of acute watery diarrhea in the 2- to 4-year- old age group in the reporting of cholera greatly reduces the specificity of reporting. For management of cases of acute watery diarrhea in an area where there is a cholera epidemic, Cholera should be suspected in all patients. 37 APPENDIX A.8 HOW DOES SURVEILLANCE CASE DEFINITION RELATE TO SENSITIVITY AND SPECIFICITY? MEASLES Clinical case definition • Any person with fever, and maculopapular (nonvesicular) rash, and cough, coryza (runny nose) or conjunctivitis (red eyes), or • Any person in whom a clinician suspects measles infection. Laboratory criteria for diagnosis • At least a fourfold increase in antibody titre or • Isolation of measles virus or • Presence of measles-specific IgM antibodies Case classification • Clinically confirmed: A case that meets the clinical case definition. • Probable: Not applicable. • Laboratory-confirmed: only for outbreak confirmation and during elimination phase. A case that meets the clinical case definition and that is laboratory-confirmed or linked epidemiologically to a laboratory-confirmed case. MENINGOCOCCAL DISEASE Clinical case definition • An illness with sudden onset of fever (>38.5°C rectal or >38.0°C axillary) and one or more of the following: • Neck stiffness • Altered consciousness • Other meningeal sign or petechial or purpural rash • In patients younger than <1 year, suspect meningitis when fever accompanied by bulging fontanelle. Laboratory criteria for diagnosis • Positive CSF antigen detection or • Positive culture Case classification • Suspected: A case that meets the clinical case definition. • Probable: A suspected case as defined above and: Turbid CSF (with or without positive Gram stain) or ongoing epidemic and epidemiological link to a confirmed case • Confirmed: A suspected or probable case with laboratory confirmation. 38 PART B How to Prepare a Surveillance Project: Operational Aspects P art A addressed the concepts of surveillance and the “ideal” way of implementing a surveillance project. In Bank operations there are multiple con- to determine (a) the state of the current system, (b) the desired characteristics of the “ideal” system, and (c) strategies for attaining a better system. straints, related not only to the Bank style of doing business but also to clients’ demands and the pres- Do I need to know all health data systems sures of prompt and timely delivery. These that exist in the country? circumstances influence project preparation: Techni- It is important to know the current data systems cal aspects, information needs, and loan preparation because they can be used to feed the epidemiologi- processes must be balanced against each other. cal surveillance system. An information system can be built to link those that already exist; in doing so Part B offers a rapid surveillance system assessment there will be more information available for policy within the usual time and cost constraints of project and decisionmaking purposes. preparation. The most common surveillance issues that may be encountered are discussed, as are the The most common data systems are: main decisions necessary in project implementation. 1. Mandatory disease notification systems This chapter outlines the professional expertise 2. Vital statistics needed for missions, where to find such profession- als, as well as the corresponding terms of reference. 3. National laboratory systems The most common training and staffing needs are 4. Vertical programs indicated. Projects might consider funding such training and staffing to assure a successful project 5. Periodic surveys and good system performance. Part B also touches 6. Hospital discharge information systems on assessment of project progress and impact, and itemizes the most common budget lines that should Current system needs assessment. facilitate the project costing process. Finally, all these What should I look for? elements will combine to outline the main condi- The seven elements of surveillance are: tions for successful project implementation. 1. Detection and notification of a health condi- tion or event Where do I begin? When preparing a project to strengthen a national 2. Epidemiological, clinical, and laboratory in- surveillance system several main steps are necessary vestigation and confirmation 39 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS 3. Data collection and consolidation • What were the selection criteria? Who was part of the selection committee? 4. Data analysis 5. Reporting • Are there also syndromes under surveillance? 6. Data transmission, communication, and feed- • Are these diseases and syndromes reported back nationally? 7. Resources • Besides this set of health conditions reported nationally, are there more reported only at the 8. Connection to action state and local level, or both? Based on the above seven elements of surveillance there are four main areas to assess: • Do specific surveillance guidelines exist? 1. Communicable disease and NCD risk factor • Are there systems for surveillance of commu- surveillance nicable diseases besides the mandatory 2. Laboratory network notification system (such as vertical pro- grams)? 3. Information and telecommunications system 4. Economic analysis Organization of the system • How is the system organized? In this paper these four areas will be referred to as the “epidemiological surveillance system.” Due to • Is there a clear definition of the tasks and re- time constraints in Bank operations, it is not gener- sponsibilities of the three levels of the system? ally possible to fully assess the system as • Is there clear assignment and awareness of recommended in appendix A.6 and as described in responsibilities? Do providers know their re- various documents cited in this toolkit. However, sponsibilities? there is a set of core information needed to establish the objectives of the project and to identify areas for • Are those functions adequate for the surveil- improvement (WHO 2001a). The relevant questions lance process? are presented below. • Does the national level recognize and under- stand the need for a good relationship between Communicable Disease Surveillance the national and state levels? Systems The assessment should strive to answer the follow- • Are the personnel at all levels of the system ing questions (based on Koo and Ostroff’s report No: committed to data collection and disease sur- 19154—for World Bank 1999). veillance? Policies and conditions under surveillance Reporting procedures and quality of data • How many health conditions are notifiable at • Are there standardized reporting forms? Are the national level? they nationally adopted, maintained, and • Are the notifiable health conditions well de- used? fined, and are definitions properly applied by • Is the information that is collected adequate reporting personnel? for action to be taken? 40 • Is there too much or too little information? numerical summaries, or do they include more sophisticated analysis and interpretation? • What is the periodicity of reporting? • What is the periodicity of the dissemination? • Are there substantial lag times in the report- ing system? • To whom is information distributed? • Is there zero reporting? (See definition in glos- Capacity issues sary, appendix B.7.) • How are data transmitted (fax, telephone, • What are the main sources of reporting data? mail, vehicle, Internet)? Does the private sector also report? • Does the system have adequate personnel in • Are data reported in a way that is easy to in- terms of quantity and quality to perform sur- terpret? How are data reported— veillance tasks? electronically or on paper? • How many staff are at the national level, and • Are reporting procedures consistent and stan- what are their profiles? How many staff are dardized? in each state or local epidemiology depart- • Are reported cases in concordance with the ment, and what are their profiles? epidemiological profile of the states and • Do they have computers? states? • Do they have standardized software, no soft- ware at all, or various levels of software? Disease investigation: data use • Is the investigative capacity adequate? • Provide case studies of recent events that stressed the system—where it failed or per- • Is the investigative response timely? formed well. • How much of the information collected is ac- tually used for reports, public health action, Noncommunicable diseases and behavioral or research. and other risk factor surveillance There are countries with epidemiological profiles • Do investigations lead to public health ac- that justify surveillance for NCDs and their risk fac- tions? tors Countries in Eastern Europe, Latin America, the • Who is responsible for case investigation? Are Middle East; and China have all undergone the tran- jurisdictions clearly drawn? sition from a disease burden largely attributable to communicable diseases to one primarily due to • Are there regular interactions between the NCDs (such as heart disease, diabetes, cancer, and public sector and other groups (for instance injuries). A public health surveillance project can academic centers and medical organizations)? help countries start or strengthen NCD surveillance • Is there a core team with investigative capac- and BRFSSs. ity at the national level? Most of the questions raised above for communi- Information dissemination cable disease surveillance—for instance • What kind of reports does the national epide- organization, reporting, dissemination, capacity— miology unit produce? Are they simple also apply to NCD surveillance. However, NCDs differ 41 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS from communicable diseases in that most cannot NCD morbidity be cured. Disease investigation is not usually a com- • Is there any information about the prevalence ponent of NCD surveillance, and public health of NCDs in the population? actions focus on primary prevention. NCDs can be • Is there any information about the prevalence entirely prevented through lifestyle and behavior of undiagnosed disease? change. Early diagnosis and adequate management are important for secondary prevention—for prevent- • What sources of information are used? Is the ing the complications they cause (heart attacks, source self-reported information or health strokes, blindness and amputations, among others). facility information? Hospital discharge sur- Specific issues that should be addressed include: veys, or ambulatory surveys? Behavioral and other risk factor surveillance NCD control • Have any surveys—national, state, or local— • Is there a survey or routine information col- been conducted that address behaviors? How lected on treatment and control of NCDs? many? Are there plans to continue the surveys? • Will these surveys be periodic, or are there Organization and data utilization • What is the link between those who do NCD plans to make data collection continuous and systematic? and BRF surveillance, and those who develop and implement prevention and control activi- • What risk factors are included in the survey ties? Is there good communication between or surveys? Is the information collected just these departments? about behaviors, or are physical measure- ments (such as weight or blood pressure) • Do those who work in prevention and control included? contribute to the development or modification of the data collection instruments? Does the • Have any clinical samples (such as cholesterol information collected address their needs? or glucose) been collected? • Are the data utilized to improve prevention • Are BRFs limited to NCDs, or is there interac- and control? tion with communicable disease programs and collection of key communicable disease • Have priorities been set and criteria developed behavior data (such as sexual behaviors and for measuring success against surveillance hand-washing)? goals for NCD? (See appendixes A.3, A.5, B.4, and B.5 for more in- Prevention and control activities formation on behavioral and other risk factor • What types of health promotion activities does surveillance.) the health department carry out? Are there any school health activities, workplace activities, NCD mortality activities in health clinics,or public service • Is there a periodic assessment of mortality announcements in the media? from NCDs? • More specifically—what work is being done • How complete is death registration? How ac- to reduce tobacco addiction? Are there any curate is classification of cause of death? smoking regulations? 42 • Are there activities to encourage physical ac- laboratories, this temptation should be counterbal- tivity, promote injury reduction (such as seat anced by the critical need to invest in personnel and belt campaigns), or better eating habits? training to efficiently and effectively use existing laboratories. • What about treatment of NCDs such as dia- betes and hypertension—is identification and Information and telecommunications treatment included in the primary health-care system package? There are many components of the information and telecommunications system. The most important is Laboratory network staff trained in the use of data and information tech- Usually the national laboratory system is comprised nology. Other important aspects include the of different types of laboratories, such as national availability of desktop computer equipment and soft- reference laboratories, public health laboratories, ware, and the overall communications infrastructure entomological units, zoonosis control centers, blood (paper mail, fax machines, e-mail, Internet, and so banks, and biosafety laboratories, among others. Due on). to limited project preparation time, it is advisable to assess a representative sample of laboratories at each Depending on the resources available, countries have corresponding level of the system, rather than the adopted a variety of different models for collecting entire laboratory network. Concurrent with the and analyzing data. At one end is a highly central- Bank’s assessment a situational analysis should be ized approach, such as where most of the work is conducted by authorities in the national laboratory done at the national level. At the other end is a de- network. There should be consensus between the two centralized model where states or local levels have assessments. staff and equipment that allow them to manage their own data. There are also hybrid models where larger The assessment should review: states and local levels manage their own data, while • Building facilities and working conditions smaller states rely on national staff, or smaller local • Laboratory equipment and reagents levels rely on state staff. • Training of laboratory staff and whether there is a sufficient number of laboratory personnel The questions that should be answered with respect to the information and telecommunication systems • Diagnostic capability (speed of diagnoses, num- fall into three categories: ber of diseases diagnosed, and major gaps) • How are data collected and reported to local, • Reporting (links up and downstream, timeli- state, and national health authorities? ness of reports, ability to communicate • Who is responsible for managing, analyzing, emergencies) and interpreting data? • Participation in national quality programs • How, in what form, and to whom are results • Laboratory management, quality control pro- communicated? cedures, proficiency programs Responses to these questions should be used to de- termine what infrastructure (staff, hardware, While the client may be tempted to spend large software, telecommunications links) are currently amount of resources on renovating or building new available and what will be needed in the future. 43 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS Data collection • What about the general public? Are summary Data collection can be paper-based, electronic, or reports prepared and published? Are they some combination thereof. For example, notifiable made available on the Internet? disease surveillance may use an Internet-based elec- • Is there effective communication between the tronic system, while NCD surveillance may use a field health department and the media? Is the me- survey with information initially collected on paper dia utilized for public health messages? and later entered into a computer. • For each health data system identified, how • Are health programs in the communication does information flow—who reports the data, loop? NGOs? Communitinues? and how (and on what medium—paper, fax, e- mail, Internet-based data entry) is it reported? Computer equipment • How do the data get to the state or local health • What kind of computer and telecommunica- department? tions infrastructure is available or needed to support and expand the data collection, analy- • How are these data then communicated to the sis, and information dissemination efforts? national health authority? • Do states and local levels have the staff and • Where and when is paper, fax, e-mail, Internet equipment needed to collect and analyze their used? own data, or will this be done for them at the • Does the current system allow easy querying national level? or correcting of data? • How will sensitive and confidential data be se- cured? What safeguards are in place to assure Data analysis and interpretation that no breaches of confidentiality—acciden- • Once the data are collected, who does the tal or intentional—occur? analyses? Is it expected that staff at the na- tional level will do all analyses, or should state In preparing for the future it is important to think and local health departments be able to pro- creatively about the role the Internet may play. A duce their own analyses and reports? number of national systems have been, or are being, • Are health program staff involved in analysis, developed that use the Internet to collect data di- interpretation and reporting, or is it all done rectly from health care providers and local by surveillance staff? authorities to disseminate preformatted reports and analyses based on those data, and to allow users to Data dissemination and communication request custom analyses of data. For such a system • Once the analyses are completed, how are re- to work effectively, providers and users of data will sults communicated to potential users? Are need Internet access. Application development, da- state and local staff, and individual data re- tabase management, and security are best handled porters given routine feedback based on the centrally because of the complexity and expense in information they collect? How do they receive setting up such systems. Because local and state gov- the information? Are reports printed on pa- ernments do not need to create and manage their per and mailed to them? Are they faxed or own separate infrastructure there can be substan- sent via e-mail? Are they accessible on the tial cost savings and increased managerial efficiency Internet? over the long term. 44 What are some general issues and needs of appropriate information for control programs, al- the surveillance system? ternative methods of surveillance (such as sentinel Coordination and standardization site surveillance) that provide higher quality data • Does the system have leadership and coordi- more efficiently can been devised. nation from the national level? Are data collected nationally, representatively, and in In addition to consolidating information on any par- a uniform fashion? ticular disease, the system should be streamlined to avoid duplication—for instance multiple reporting • Do all states and local levels collect, investi- systems for the same disease. gate, record, and report in the same fashion? • Are there standard definitions and guidelines Training and capacity building easily accessible for notifiable diseases? • Usually there is a great need to have well trained personnel at all levels of the system. • Are there standardized disease investigation forms for each notifiable disease? Which kind • Assess the number of persons involved in dis- of data do these forms include? ease monitoring. • Are disease reporting and laboratory data • Have cases been properly investigated? linked? How simple and successful is this link- • How skilled are personnel at the national age? level? Integration • Identify the critical staffing needs and type of • Are the main components of the system (the training needed. surveillance system, the disease-specific pro- grams, and the national laboratory network) Analytic capability working in an integrated manner and effec- Systems often generate numbers and disease rates, tively sharing information? but lack data analysis and interpretation. • Are data sufficient to develop meaningful in- • Is there a link to datasets in place? formation on risk factors and provide diagnostic confirmation in order to appro- Consolidation and assessment priately plan prevention and control This assessment should include a review of each dis- activities? ease, why it is being reported, what actions need to be taken at the local, state, and national levels and • Is there a GIS or capacity for developing one? how data should be reported. Information needs may vary depending on the disease and on the level of Quality control the health system (see table 1, appendix B.6). Sur- • Is there a quality control system in place? veillance information generally gets consolidated and • What proportion of cases meet case defini- condensed as it moves up the pipeline from the lo- tions for disease? cal to state to national level. “High volume” conditions such as influenza, diarrheal diseases, and pneumonia, may overwhelm surveillance personnel For instance, diarrhea is usually defined as “pres- if detailed information is collected about every single ence of illness for at least 24 hours with more than case. In order meet public health needs and provide three loose bowels in that period,” so unless charts 45 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS are reviewed there is no way to tell what proportion viders to report certain diseases and information that of cases meet the case definition. may otherwise be confidential requires a basis in law, Box 6 Investigation • Does the system have outbreak response ca- LESSONS LEARNED FROM JEAN-JACQUES DE pacity at all levels, and conduct ST. ANTOINE, TASK MANAGER FOR PREPARATION epidemiological studies to address priority OF THE BRAZIL’S DISEASE SURVEILLANCE PROJECT diseases? (VIGISUS) • Do personnel know their main tasks and de- In 1997, we received a request from Brazil basically saying: “Our disease surveillance system is 20-years-old. We need to gree of responsibility when an outbreak modernize it; we would like to make it become the Brazilian occurs? CDC. Can the Bank help us with that?” • How many investigations have been per- “Of course we will help you,” I replied (not having even written a PCD for the project). The challenge was to agree on a vision of formed at the national level? what the system should look like in 10 years, what would need to be done technically and financially, at what pace, and who would • Are there written reports or publications of have the responsibility to do what at the federal or the local level. these investigatiμ ons? The technical work consisted of compiling the best package to strengthen skills at the center, as well as regional and municipal staff, to improve the collection, transmission and analysis of data Data reporting and feedback and create mechanisms to ensure the link with decision-making • Does the system produce periodic bulletins required to address diseases (either prevent diseases, deal with and provide feedback to disease reporters? outbreaks of communicable diseases, or reducing the risk factors for noncommunicable ones), and finally modernizing the laboratory network. The role of the various levels of the system • Are data appropriately summarized and pre- (federal, state, and municipal) would be reviewed. The work with sented and easily available for decisionmakers partners in CDC and PAHO gave me great professional satisfac- to take appropriate control and prevention tion. The work with the client presented the challenge of actions? addressing the needs of a sophisticated client in an immense country, making sure to keep project design fairly simple and flexible. It was a great learning experience for me. Based on that Alternative surveillance methods experience, if I had a chance to do a second project, I would: As mentioned above (in discussion of consolidation • Fully evaluate the existing system as part of project and assessment), there is a need to determine the preparation or sector work to make things easier later. I would involve the client as much as possible in the exercise. best methods for collecting data of sufficient quality • Build strong partnerships with CDC and the WHO and its for use in developing control programs. regional offices, the key actors in this field. • Are appropriate alternative methods of sur- • Get the best consultants (they need to have both the veillance such as sentinel networks used theoretical and practical knowledge and be able to sell their appropriately for influenza or diarrheal dis- ideas to the client). eases? • Press the client to limit the number of disease and risk factors under surveillance, but pick them well. • Are these alternative systems linked to the • Design a project with a few key activities that are sure to national laboratory network? have a strong and lasting impact in the country (training, improvement of data collection, and upgrading of Regulatory aspects laboratories). A system of mandatory disease notification means • Pay close attention to what should be done at different that notification is compulsory. Obliging health pro- levels of the system (national, state, and municipal).” 46 ideally. Most countries with this type of reporting a large number of health conditions under surveil- have some type of statutory provision that enumer- lance since it may be difficult to properly address ates exactly how, to whom, and within what period and respond to each one. Criteria should be applied the reporting must occur. In the United Sates, for to determine high-priority events for surveillance, instance, this power resides in the states, and report- and the system should rely on alternative surveil- ing requirements vary from state to state (Matthews, lance methods, such as sentinel sites, when needed. Neslun, Churchill 2000). These sentinel sites are often more successful when implemented gradually. What are the main decisions and options for project implementation? Phasing by region or diseases versus phasing Responses should be consistent with the level of de- by activity velopment of the health service infrastructure, There are several options to consider. First, the personnel, available funding, and project duration, project may be implemented by geographic area. among other factors. This is a difficult option, because most of the time states or local levels are not willing to wait for “their Flexible project design versus rigid structure turn.” The second option is to implement the project One alternative project design is a federal, fully de- for a few diseases at a time. This option could po- tailed, and standardized national surveillance tentially be used, but probably not when financed system. This approach might not properly fit the by a loan, since phasing by disease could require system needs, given the specific gaps and capacity costly duplication of training efforts, standardiza- of different states and local levels. In addition, de- tion of procedures, and many other activities related spite the current climate of decentralization, local to implementation of the system. A third, and possi- surveillance needs are often unrecognized at the bly best, option is to implement the project for high national level. A top-down approach could weaken priority events, or to begin in sites where the maxi- local ownership since the local level might not have mum number of cases would be detected, using the the opportunity to articulate its needs. At the same least effort. Certain project activities could then be time, a national surveillance system requires an implemented gradually (for example, training pro- overall conceptual framework and standardization grams, sentinel networks, telecommunications of data collection, laboratory procedures, case defi- systems, and NCD surveillance, if applicable). nitions, and basic norms to be followed by all participants of the system. The most common ap- Communicable diseases versus noncommuni- proach is a project partly predetermined and partly cable diseases flexible during implementation, based on state and Addressing NCDs and BRFs depends on the epide- local level development plans. This alternative bal- miological profile and development of the country. ances the need for national consistency with the Middle-income countries with longer life expectan- opportunity to respond to local needs and targeted cies and increasingly urban populations have interventions. reached the point where chronic diseases and dis- eases related to lifestyle cause the majority of deaths Comprehensive versus focused and illnesses. Understanding current disease pat- The surveillance system should be developed ratio- terns and related behaviors in those countries and nally, based on national capacity and long-term monitoring of changes in these patterns cost-effectiveness. It is not always appropriate to have and behaviors over time is critical to effective plan- 47 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS ning and execution of appropriate public health in- economic justification of the surveillance system is terventions. Most of these countries are not prepared based, a quantitative analysis can be carried out to in this field. Therefore, an incremental, strategic ap- help determine the optimal scope of surveillance and proach to chronic disease surveillance and disease control. The establishment of priorities and associated risk factors is advised. The project could the final decision of which diseases to include can begin by setting priorities in chronic disease con- be based on the following criteria: (a) disease im- trol and prevention, determining staffing needs, and pact on national DALYs; (b) approximate then implementing an appropriate training pro- cost-effectiveness of control interventions; (c) out- gram. break potential of emergent diseases; (d) plan or potential for eradication; (e) vaccine preventability; Private versus public intervention (f) classification as an indicator or risk factor for an Health surveillance and disease control are public important disease; and (g) the probability that im- goods and are core areas of responsibility of the na- proved surveillance would lead to better control (that tional ministries of health, and their state and local is, reduced mortality, morbidity, or disability) of the counterparts. Nevertheless, there may be ways in disease. which private health insurers could become partners in the system and contribute through cost-recovery. This analysis should take place early in the project Clearly, health insurance providers have a vested in- preparation cycle in order to have an impact on the terest in seeing that disease incidence is reduced design of the system, both in scope and method, and through surveillance, control, and public health pro- should use a participatory process, involving the grams, and may be willing to pay for these services stakeholders in the analysis. This early involvement through contributions or levies on insurance premi- will ease the process of discussing the final list of ums. Health insurance providers could be contracted health conditions to be included in the system as to perform certain services. well as the corresponding surveillance methods. What about the economic analysis? This process was successfully carried out in the One of the most common problems observed in sur- preparation of a World Bank surveillance project. veillance systems is a high number of health The original list of 50 notifiable health conditions conditions under surveillance that burden the sys- targeted for surveillance (too many for an efficient tem and prevent it from working efficiently. Often, system) was reduced to 29 for notification, and 4 to strengthening surveillance is automatically associ- be surveyed by alternative methods such as sentinel ated with increasing the number of health conditions sites. included in the system. This can become a difficult issue for negotiation; it is crucial to give evidence of Sustainability analysis the negative impact of choosing too many health Aside from quantitative analysis to prioritize the conditions for monitoring. health conditions targeted for surveillance, a sustainability analysis should also be undertaken. In To establish priorities and to address the cost-effec- other words, will the changes initiated by the project tiveness of the proposed interventions on which the be sustainable?7 7 This two-part economic analysis (carried out by G. Beeharry and D. Akhavan) can be found in the Project Appraisal Document (PAD) of the Argentina Public Health Surveillance and Disease Control Project, Report No: 19154. 48 What expertise do I need on missions? Finally, there is a new effort by retirees from state The minimum core technical personnel necessary and federal public health agencies in the United to prepare the project include: States to establish a nonprofit consortium in order • A communicable diseases surveillance special- to continue their contributions to public health. This ist and, in some middle-income countries, a organization, Public Health Emeritus, may be noncommunicable disease and BRF surveil- reached in the United States at (973) 972-4422. Terms lance specialist. of reference for some specialties can be found in appendix B.3. • A laboratory expert with experience in labora- tory surveillance. National stakeholders need to be involved, • An information technology expert with expe- right? rience in designing and establishing Right! The system assessment described in the be- telecommunications systems. In less-devel- ginning of this section will provide the minimal oped countries this specialty may be replaced information needed to establish the project options by an information specialist, since these available based on a needs assessment of each state countries may lack the capacity to implement in terms of resources (personnel, equipment, infra- and sustain a telecommunications system. structure, and financial) and perceived and actual disease priorities. In one state the critical need may • A health economist to develop a cost-effec- be personnel, in another computers, while in another tiveness and sustainability analysis. it may be improved laboratory capacity. One model Understanding of surveillance and disease will probably not suit the needs in all states, so ac- control is desirable. tive involvement of the national stakeholders may Ideally, the consultants should not only have knowl- help determine the most appropriate and suitable edge about the subjects but also practical experience, model. This has two main benefits: better data are especially in developing countries. obtained for decisionmaking in key areas for im- provement; and ownership and commitment of the Where can I look for this expertise? key project implementers is established through There is no organized network or directory of sur- making them part of the team-based decisionmaking veillance experts. However, there is a very effective process. informal network. One can access the informal net- work by contacting the many national and How do I involve the stakeholders in the international agencies that are in the forefront of process? public health activity, such as the CDC in the United Rather than addressing all diseases, the evaluation States, parallel organizations in other countries, and should focus on certain diseases and can be con- the WHO and its regional offices, which provides a ducted in specific high-, medium-, and low-capacity Web site directory of national surveillance centers states, as well as at the national level. A stakeholder (www.who.int/emc/surveill/mohglobal.html). Nu- workshop should be planned to address questions merous for-profit and not-for-profit consulting firms regarding the main problems assessed by the Bank can also provide or identify expertise. Schools of team (see an example of such a workshop in appen- public health are a resource, as are specialists of na- dix B.2). Every assessment should include tional surveillance systems, especially from countries participation of national experts and personnel in- that have proven, high quality, surveillance systems. volved in the national surveillance system. 49 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS Box 7 After these activities, the team should be able to iden- LESSONS LEARNED FROM MARCELO BORTMAN, tify the system’s capacity and its main problems, and start discussing areas in need of investment, as well COORDINATOR FOR THE PUBLIC HEALTH as to create ownership and support from the main SURVEILLANCE AND DISEASE CONTROL PROJECT IN ARGENTINA (VIGI-A) stakeholders for project implementation. Argentina is a federal country in which provincial states have What are the staffing needs? been responsible for health-related services since Argentina was The most common specialties are: made a republic. This “independence” results in significant differences among the health services provided by each state. • Epidemiology Thus, the surveillance system suffered not only problems of • Infectious diseases quality and coverage, but it also struggled with structural differences among states with substantial differences in the • Statistics performance of their surveillance systems. Although well- developed states had better coverage and greater capacity for • Data entry analysis and response, many states lacked capacity. • Computer support Therefore, the following was key for a smooth implementation and involvement of the states: • Microbiology (relationship between epidemi- • Consensus among states regarding surveillance norms. ologists and laboratory technicians) Support from the state level was key for project success and consistency. • Editing (editing epidemiological bulletins) • States were involved in the selection of trainers and development of training plans. Staffing needs at the national, state, and local levels should be identified by task and quantified in terms • The training program was designed to develop incremen- tally, with intermediate and final products identified. of personnel per unit population (such as one state- Jurisdictions, epidemiology instructors, and epidemiology level epidemiologist per 500,000 population, one personnel were involved in the design of this program. computer-support person per 1 million persons) and • Ensuring participation of state authorities in the selection specific circumstances (for instance geographic bar- of trainers, requiring a screening for knowledge of riers, rural as opposed to urban) should be epidemiology prior to hiring. recognized and addressed. • Internet-based surveillance software was developed for three standard modules encompassing most of the system: mandatory notification, active surveillance, and sentinel At the national level a core group with technical ex- surveillance. pertise is required to provide leadership and • Integrate laboratories, clinical personnel, and epidemiolo- supervision. At the state level technical people are gists to create independent strategies and protocols for needed to support surveillance activities (to analyze, each of the conditions to be under surveillance by the investigate, report, respond, and provide feedback sentinel surveillance units. and technical support to the local level). At the state level the project will need at least an epidemiologist responsible for project implementation and collabo- Due to the complexity of surveillance systems and ration with the Project Coordination Unit. Depending the relationship with other areas of the health sys- on the size of the state, it may also require a as well tem, project preparation should not be rushed; as another epidemiologist to assist with training. rushing could result in overlooking the above-men- tioned issues. If necessary, the first year’s loan funds The number and profile of staff for surveillance or could be used to complete the needs assessment. project implementation depends on many factors, 50 from the degree of decentralization of the country, cording to priority for system development. Poten- to its size, population, and development. But there tial indicators for assessing progress in the system is always a common need—training. Regardless of development include: (a) definitions and coding the country characteristics, a national surveillance standards defined and approved; (b) key personnel system needs to have a team of field-trained epide- trained in various areas of expertise and; (c) up- miologists who are competent in the practical grading a certain number of laboratories to application of epidemiological methods as they re- biosafety levels 3 and 2, and other laboratories to late to a wide range of contemporary public health biosafety level 1;8 (d) number of case reports from problems. each area reporting (e) number of cases from each area with completed disease investigation and ap- What are the most common training needs? propriate response (f) epidemiological bulletin Most countries lack epidemiology expertise, so development and production of a certain number projects should consider training actions in several of bulletins; areas. There is often a strong desire on the part of countries and Bank personnel to invest in renovat- Impact ing or building new facilities, particularly Given the nature of the investments often required laboratories. This temptation should be resisted. to develop or strengthen surveillance systems, it may Instead, it should be recognized that competent and not be possible to measure the impact of the project qualified personnel, including laboratory personnel, on surveillance during its short lifetime. Much of the are key to effective surveillance (see table 7). Train- project’s lifetime is devoted to preparing the system; ing is fundamental to the success of any surveillance only when the project is close to an end will we start project. to see results. Therefore, it is advisable to be conser- vative in defining impact indicators, and to place What are the most common budget lines for greater emphasis on process indicators. The indica- public health surveillance? tors used depend on the system and its resources. (table 8 Common Budget Lines for Public Health Impact measures should be quantifiable, including Surveillance) items such as: (a) Notifiable disease data appropriately utilized How can I assess project progress and (for instance, X percent of cases of invasive impact? meningococcal disease detected have been investigated and appropriate control measures Progress instituted); There is a wide array of activities that can be imple- mented to increase efficiency, and strengthen and (b) Surveillance system detects at least X percent support surveillance systems—from training, to of invasive meningococcal disease per 100,000 definition of surveillance norms and upgrading inhabitants. This level should be met or ex- laboratory networks and communications systems. ceeded in Y percent of the provinces, B percent All these activities should be included in project culture confirmed, and C percent of isolates implementation plans, and should be phased ac- sero-grouped; 8 Four biosafety levels exist depending on laboratory practices and techniques, safety equipment, and laboratory facilities (CDC/ NIH 1999). 51 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS Table 7 Training and targeted personnel Training Targeted personnel Basic epidemiology Local (health center or hospital), state, and • Health indicators laboratory personnel, and the outbreak control team • Information systems State-level epidemiology training Professionals at the national and state levels (working in • Epidemiologic methods epidemiology) • Epidemiological studies and types of error • Epidemiology of communicable diseases and chronic illnesses Basic principles of outbreak investigation (level I) State-level doctors and nurses who would be future trainers • Case analysis • Description of outbreaks • Causes • Epidemic curves Principles of outbreak investigation (level II) State personnel, health specialists, and outbreak control team who To avoid long absences of professionals from the workplace, this would be future trainers training can be developed as 2 two-week courses, separated by a 6-month field project, and a one-week follow-up course Outbreak investigation (advanced level) Epidemiologists, infectious disease specialists, laboratory experts, • FETP entomologists at national epidemiological unit—all of whom • TEPHINET (usually two-year program). (See appendix A.4 make up the national team to assist the country in the most for more information.) difficult outbreaks Laboratory biosafety Laboratory personnel who would become biosafety specialists, One national and one international instructor (presence of the providing training to other personnel. international instructor depends on national capacity in the subject) would provide training in instrument handling, and methods and equipment for biosafety Laboratory reporting systems Use of new computerized laboratory reporting system Future trainers from 1 state laboratory and national laboratories Training in information systems for state workers State computer experts who will then train and support other • E-mail and the Internet computer personnel at the state and local levels. • Network security • New applications Software for surveillance systems Data entry clerks and computer software personnel to operate the • Basic operations and use of the computerized surveillance disease notification software at the national, state and local level network • Transfers and protection of databases • Basic maintenance • Data input and output (one-week national training followed by a three-day evaluation six months later) Data for decisionmaking Heads of epidemiology, working with state programs and Collection, analysis, and use of data. statistics, and public health specialists from national institutes and MoH Management course • Improvement of management skills at the state level Directors of epidemiology programs, and state and national laboratories Continued on next page… 52 Table 7 Training and targeted personnel (continued) Publication of bulletins or reporting system for At least one at the state level, and three at the national level surveillance data • Design standards • Presentation of tables and graphics • Report writing Training to implement NCD and risk factor surveillance Public health professionals • Establish data needs, priorities and management needs for NCD control • Training in data collection, follow-up, and so on • Instrument design (questionnaires, scales, reliability, validity, sampling methods, and so on) • Data format, record keeping, aggregation, and data analysis Training for health promotion Epidemiology unit staff • Communication skills TV and radio journalists • Basic training in surveillance and disease control • Basic training in behavior change and priority BRFs. Table 8 Common budget lines for public health surveillance Budget line item Sub-items Personnel (salaries or per diem)8 • Case or outbreak investigators • Surveillance officers • Data managers or statisticians • Laboratory staff • Trainers • Editors Workshops or meetings for advocacy or coordination • Planning workshops • Subnational training or planning workshops • Clinician advocacy • Coordination meetings • Newsletters (surveillance advocacy and project accomplishments) Equipment (capital costs) • Specimen carriers • Cold chain • Vehicles, motorbikes, boats, bicycles • Laboratory equipment • Computer equipment • Communications and data transfer equipment Operations and supplies (recurrent costs) • Specimen kits • Specimen collection and dispatch • Specimen shippers (for instance cross-border shipment) • Laboratory consumables • Computer maintenance • Communication equipment and maintenance • Creation of standard forms and feedback • Social mobilization and advocacy • Materials and activities • Ad hoc reimbursements for notifications Continued on next page… 53 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS Table 8 Common budget lines for public health surveillance (continued) • Vehicle maintenance and spare parts • Petrol (gasoline) • Transportation of equipment • Publication and distribution of surveillance guidelines/norms • Epidemiological bulletins Training Personnel involved in surveillance at national, state, and local level, and laboratory staff Source: Adapted from WHO 1999b. (c) Three cases of bacterial meningitis reported data. Communities are not involved in surveil- for every case of meningococcal disease rec- lance or disease control. ognized and X percent culture confirmed and; 2. The surveillance system is fragmented and un- (d) An etiologic agent identified in at least X per- coordinated across all levels of the system and cent of stool cultures obtained from all between epidemiological and laboratory sur- persons identified with diarrheal diseases at veillance. Thus duplication of activities, highly sentinel sites. variable information, lack of standardization, and inefficient use of resources are common. What about project evaluation? 3. Surveillance systems are often overly ambi- During project implementation the capacity of the tious and unrealistic, with too many health system should be assessed again, not only to evalu- conditions under surveillance. They are often ate project impact but also to create a culture of geared toward producing large numbers evaluation. The MoH needs to understand the value rather than useful information. of a surveillance assessment and lead the process. 4. Integration with the health-care delivery system Evaluation should involve the main stakeholders, (public and private) is weak or nonexistent. those who will benefit from the surveillance system. 5. Laboratory support for surveillance varies The assessment team should be multidisciplinary greatly between diseases. Results are often de- (such as epidemiologist, laboratory specialist, tele- layed: timely, reliable confirmation of communications specialist) and consist of national suspected cases to those who will make deci- and international expertise. The WHO and CDC can sions and take action is rare. Poor conditions be involved and provide coordinated support (see of biosecurity are common. appendix A.6). 6. Data management, transmission, and utiliza- What are the most common problems in tion are usually weak . Much of the data surveillance systems? collected are not analyzed or used for action. 1. Surveillance activities are usually centrally con- Minimal analysis and use is generally found trolled by the MoH; other players have a limited at the national level, while at the state and role. The national level makes decisions based local levels there is nothing but data collec- on data collected by the local level, yet the lo- tion. Usually the data transmission system is cal level usually receives no feedback on that rudimentary and introduces inaccuracies, and 54 there is a lack of methods for easily querying 8. Worker motivation in many places is low. or correcting data. 9. Information obtained is not linked to and uti- 7. Training and capacity building is usually a low lized for public health action. priority. This is more evident at the state and 10. The private sector and the community are not local levels. Often clients would rather use re- usually involved in disease surveillance. Most sources to upgrade facilities or even build new systems rely almost entirely on the public ones than invest in personnel and training. health system as the sole source of information. Box 8 What are the main conditions for successful LESSONS LEARNED FROM JARBAS BARBOSA project implementation? DA SILVA, JR., DIRECTOR OF THE NATIONAL 1. An evaluation of the system performed. If there EPIDEMIOLOGY DEPARTMENT OF BRAZIL are resources and time, you ideally undertake all that is suggested in appendix A.6. If you The decentralization process in epidemiology, surveillance, do not have the time, and usually you do not, prevention, and disease control is very different from decentrali- zation of health-care delivery. Faced with a decentralization follow the assessment described in this part process in these areas, in a country with the geographic and also see appendix B.1. Get the client in- dimension, socioeconomic and epidemiological diversity of volved in the exercise (appendix B.2). Brazil, is a huge challenge. 2. A well defined and agreed-on list of health con- The VIGISUS projecta has been an essential tool for enabling the “change of roles within the three levels of the system.” At the ditions to be surveyed, standardization and federal level, a higher response capacity for the most complex acceptance of case definitions and surveillance problems (for instance emergent diseases) was developed, and methods. strong leadership was established for issues of standardization and coordination, to avoid fragmentation of the system and lack 3. Sentinel surveillance. A defined, stepwise imple- of effectiveness. At state and municipal levels, VIGISUS helped develop capacity to execute the intermediate and basic mentation plan for sentinel sites, with health surveillance and disease control activities, with greater capacity conditions and sites confirmed. for anticipating problems and increased efficiency in addressing them. 4. Revised surveillance guidelines which should include “what and how,” “when, who, and If I were beginning project preparation today, I would: • Have a more detailed assessment of the surveillance where.” Guidelines should be revised by na- system (preproject) at the state and municipal levels. tional health surveillance officials, external • Based on that assessment I would create a more detailed review should take place and the final prod- design of the investments for each level of the system. uct approved by the main policy • I would define, up-front, the content of the training decisionmakers. program according to the needs of the state and municipal levels, since there were difficulties in negotiating the 5. Personnel and training. Number and profile of content with teaching institutions. staff at national and state levels, as well as a • Emphasize the importance of maintaining a minimum core training plan for the corresponding target team of Bank staff and consultants, from preparation to personnel, reporters, along with its cost. supervision, in order to have a good knowledge base of the country and the project. 6. List of laboratories targeted for improvement a Forty percent of the VIGISUS investment on surveillance is and, if possible, identification of the kind of executed at state and municipal levels. rehabilitation required. Design upfront, if 55 PART B HOW TO PREPARE A SURVEILLANCE PROJECT: OPERATIONAL ASPECTS possible, the bidding documents for labora- associations and social sectors other than tory rehabilitation. health, which may also benefit from a good surveillance system (tourism, agriculture, trea- 7. Telecommunication system defined or improve- sury, and so on). Periodical dissemination of ment of the existing one established. Design information to the press, and involving one or upfront, if possible, the bidding documents two health-related journalists, might also pro- for data transmission systems. mote the project. As stated earlier, emphasis 8. Clear definition of the roles and responsibili- should be placed not only on technical aspects ties of the three levels of the surveillance but also on the process as part of the strategy system. Often, these roles are not well defined for maximizing ownership. and task overlap is common (see appendix 10. Do as much project design as possible. A de- B.6). tailed implementation plan that includes the 9. Local ownership and commitment to the project. identification of the task, and its objectives, This can be achieved through early involve- the location, starting date and ended date, the ment of the main stakeholders in project responsible staff or entity for its implementa- preparation and decisionmaking processes. It tion, the description of the main steps, unit is important to actually visit and engage sites cost and procurement procedures, and the outside of the national capital. These activi- outputs is an important management tool for ties should also include national professional the client, as well as for the Bank. 56 APPENDIX B.1 Evaluation of the system and capacity I n practice, for purposes of preparing lending projects, the evaluation process is modified here and differs from the more “ideal” method described 3. Team composition A team of two persons should visit each of the se- lected states to conduct the evaluation. These two in appendix A.69 (CDC 2001; WHO 2001a). In order persons should have experience in epidemiology and to evaluate the system and surveillance capacity at laboratory surveillance. the state level, an evaluation of collection methods and use of information for six notifiable diseases or During this evaluation, the following questions conditions should be conducted in six locations (that should be answered: is, at the state or local level). 1. How many persons are responsible for surveil- lance at the local and state level … How? These persons should be identified by task and quan- 1. Selection of states tified in terms of personnel per unit population (for One measure of performance is whether states are instance, one state-level epidemiologist per 500,000 reporting anything to the national surveillance sys- population, one computer support person per 1 mil- tem. Select two states that are the most up-to-date lion persons). This quantification should also take in reporting (high capacity), two states that are av- into account the proportion of time actually dedi- erage (reports are delayed by four to six weeks), and cated to surveillance activities. two states that have not reported for at least eight weeks (low capacity). During this evaluation the team 2. … and for each disease or condition… should visit at least two of the local reporting areas • What are the sources of reports of this condi- in each selected state. tion (for example, hospitals, clinics, laboratories)? Are they private or public? 2. Selection of diseases • Do reporting sources know the definition? Diseases fall into three categories: (a) high numbers How well is it applied? (List the written case of cases, low specificity (diarrhea, influenza); (b) low definitions for this condition.) number of cases, high specificity (measles, Chagas disease); (c) intermediate volume and specificity • Are cases defined by status (for instance “con- (hepatitis, meningitis). firmed” as opposed to “suspected”)? What 9 Koo, D. and Ostroff, S. for VIGIA preparation mission. (See World Bank 1999—VIGIA PAD). 57 APPENDIX B.1 EVALUATION OF THE SYSTEM AND CAPACITY proportion of cases in this state are suspected, • Are there written standards for case investi- probable, or confirmed? gation and intervention? • Have local level reporters been trained in dis- • Have any outbreaks of this condition been ease-recognition and reporting? identified through this system? How were these identified, and were investigations • Is there a standardized case report form spe- conducted? Who conducted the investigations cifically for this condition, and written (was it a local, state, or national team)? instructions on how to fill out the form? • What is the time delay between the occurrence • What information is requested regarding cases or detection of a case and its being reported of this condition? to the state level? • Who generally fills out the form? • How is information about cases recorded or • How often are data reported from the local stored? (Is it computerized?) level to the state and what mechanism is used • Who analyzes the data? for reporting (paper form by mail; telephone; fax)? • How are data analyzed, and how often? • How is information transferred? • How often are the reports disseminated, in what format, and to whom? • Are case report forms reviewed for complete- ness prior to their being sent to the state level? • Are the data provided to those who report them? (That is, is there feedback of data to • Are forms completely filled out? Review a the local level and to other groups, including sample. physicians and laboratory personnel?) • Are data sent as summary or individual cases, or both? The following resources may prove useful in evalu- ating surveillance systems: • Is laboratory diagnostic testing available for this condition in the state? If not, are labora- www.cdc.gov/preview/mmrwhtml/rr5013a1.htm tory specimens sent elsewhere (where)? • What proportion of reported cases have had w w w. w h o . i n t / e m c - d o c u m e n t s / s u rv e i l l a n c e / appropriate laboratory testing? whocdscsrisr992c.html • Can case reports be linked to the correspond- ing laboratory data? If so, how? 58 APPENDIX B.2 Stakeholder Workshops Goals of the workshop • Standards for reporting or linking surveillance 1. Develop a more detailed, ideal vision for the data revised surveillance system, its desired char- • Integration with the health-care delivery sys- acteristics, and components; tem (through public and private health centers 2. Establish a system for prioritizing conditions and assistance) for inclusion in the surveillance system; and • Expected uses of surveillance data 3. Develop strategies for stepwise implementa- tion of the system. • Desired timeliness of the system Participants • Level of computerization required Representatives from national, state, and local health • Capacity needed within the MoH and at the departments. Preparation for this workshop should state and local levels to ensure appropriate be coordinated with the National Epidemiological analysis, interpretation, dissemination, and use Council or equivalent body. Other participants in this of surveillance data for public health action. workshop might include persons who represent pri- vate sources of health data (hospitals or private Prioritization of conditions for inclusion in the clinics) or academic medical societies or organiza- system tions, and health management organization. Given Criteria for selecting conditions that should be in- the activities involved in the second component of cluded in a surveillance system might include the workshop, it may be useful to invite MoH staff severity, incidence and prevalence, communicabil- with expertise in the diseases, or at least to provide ity, availability of a cost-effective control measure reports and information about these diseases. (a vaccine), societal concern, interest by the WHO or the PAHO, or ease of diagnosis. (See also appen- Issues to be addressed during the workshop dix A.6 and p. 15—Setting priorities: What are the Visions of the ideal surveillance system considerations in planning public health surveil- • Sources of surveillance data (health centers, lance?”). It is important to develop—with the hospitals, laboratories, private insurance, and participation of public health persons at local, state, personal interviews) and national levels—a method for prioritizing con- • Surveillance methods (notifiable diseases, sen- ditions that should be included in the national tinel surveillance, surveys) surveillance system. 59 APPENDIX B.2 STAKEHOLDER WORKSHOPS Table 9 shows a sample agenda for a workshop for only in certain areas of the country (where there are developing criteria for prioritizing conditions under regional problems with a specific disease or where surveillance. human or other resources are already available or can be supplied). Strategies for stepwise implementation During this portion of the workshop participants Each strategy must be very specific and detailed, with would develop strategies for stepwise implementa- the actions to be taken, by whom, and by what date. tion of revisions to the system. Not all components The strategy should also outline necessary resources of the system need to be implemented in all parts of and possible providers. the country. Some components may be pilot-tested Table 9 Sample agenda for workshop Day 1 Morning Give the group a list of five diseases and explain that, hypothetically, the legislature has said they are cutting the MoH budget. In small groups, rank these five diseases in order of priority, so that when the MoH receives the budget there will already be an idea of how to spend the money. Each group then presents their rankings and the principles and rationale used to come to those conclusions. Afternoon 1. (Individually.) Generate three criteria for selecting diseases. 2. (In groups of six.) Using criteria from individual activity above, establish a list of a maximum of 10 criteria. 3. A spokesperson from each group presents the criteria to the rest of the participants. There is no lengthy discussion, except to clarify concepts or meaning. Day 2 Morning 1. Meet in groups and try to find common categories among the lists presented by small groups the day before. 2. (Entire group.) List the overarching categories or criteria. 3. Determine whether all criteria are accounted for, and clarify the concepts or wording. Continue to collapse categories as needed. 4. Decide whether there should be a maximum number of criteria, or an appropriate system of weighting each criteria. 5. (Small groups.) Decide on the weight for each criterion (suggested: 0–5 points). 6. (Entire group.) Tally results and make decisions about weighting for each criterion. 7. Apply criteria to all conditions or diseases considered for surveillance, using the expertise of participants in the workshop or data from references or reports about these conditions and their prevalence in the country. Afternoon 1. Tally results (including the respondent or source of the numbers—state or national, for instance). Present conditions in rank order by mean or median value (number of participants who responded, mean or median score, range of values, standard deviation of responses). 2. In small groups discuss how this list should be used. Should it be used to delete or add to the list of diseases or conditions under surveillance? Alternately, should it be used to determine the mode of surveillance and the resources allotted to surveillance for that condition ( fewer resources or less frequent reporting for diseases lower on the list)? 3. Determine next steps. 60 APPENDIX B.3 Sample Terms of Reference for Specialists Participating in Preparation Missions • Evaluation of the surveillance system • Timing: frequency of reports communi- cated between levels. • Assessment of laboratory infrastructure • Computer-based information and telecommu- 4. Decisionmaking and action nications system • Decisionmakers with respect to surveil- • Noncommunicable diseases and risk factor lance; surveillance • Adequacy of information: identify infor- mation collected systematically but not • Economic analysis used; Statement of mission objectives: Evaluation of • Communication and implementation of the surveillance system decisions; and (Name of consultant) will evaluate the surveillance • Monitoring system—mechanism in place system regarding: for monitoring the implementation of de- 1. Objectives cisions. 2. Detection of events • Notifiable diseases, syndromes, and case 5. Feedback definitions • Adequacy of feedback for supervision and • Recording forms; and improvement; • Outbreaks: detection and control. • Timing: adequacy of the schedule for those receiving feedback; and 3. Reporting procedures • Indicators to define the quality of report- • Levels to which the information observed ing. is reported; • Reporting forms; 6. Resources • Means of communication used for report- • Current staff and job descriptions for ing the information to each level; each main facility and administrative of- fice; • Utilization of data; • Equipment: inventory of equipment, not- • Collation and management of data; and ing shortages; 61 APPENDIX B.3 SAMPLE TERMS OF REFERENCE FOR SPECIALISTS PARTICIPATING IN PREPARATION MISSIONS • Budget: budget allocated to the surveil- (g) Others you may think are pertinent to the lance system, including financing project mechanism. 2. Undertake a biosafety evaluation of the labo- 7. Assess the need for sentinel sites or periodic ratories, using criteria in the CDC-NIH surveys and (with the MoH) develop a strat- publication Biosafety in Microbiological and egy for implementation. Biomedical Laboratories, 3rd Edition. 8. Review the MoH proposal for a national health 3. Define specimen rejection criteria, if applicable. surveillance system. 4. Review diagnostic reagents production and 9. Provide recommendations for redesigning or suggest modifications, if necessary. improving the current surveillance system, addressing all weaknesses identified. 5. Review the plan for routine proficiency test- ing of subordinate laboratories. 10. Provide cost estimates for the project. 6. Define the needs for strengthening National 11. Propose agenda for implementation, includ- Reference Laboratories in outbreak investiga- ing selection of states. tion. 12. Identify the main risks in implementing a na- 7. Review specimen log-in and tracking, as well tional surveillance system. as management results, and suggest a com- puter-based program, if necessary. Written output: Using existing MoH documents and findings during the mission, produce a short report 8. Define the scope of public health laboratories summarizing the surveillance system to be improved within the context of the national surveillance (bullet points) for the aide memoire and a full re- system. port no later than (give delivery date). 9. Describe plans for rehabilitation and expan- sion of the laboratory network, assess Statement of mission objectives: Assessment of necessity of new infrastructure, and propose laboratory infrastructure modifications, if necessary. (Name of consultant) will assess the laboratory in- frastructure covering the following topics. 10. Review the need for laboratory personnel 1. In keeping with project objectives, assess and training, in terms of present deficiencies and describe (number, location, type, human re- project objectives. sources, technical capacity, communication 11. Define a standardized system for laboratory capacity, and so on) the current laboratory data to be used in national reference labora- infrastructure regarding: tories and in state laboratories. (a) National reference laboratories 12. Propose terms of reference for additional work (b) Public health laboratories in areas where data is not currently available (c) Entomological units or analysis needs to be completed. (d) Centers for zoonosis control Written output: A full report presenting your find- (e) Blood banks ings and recommendations, to be remitted to the (f) Biosafety laboratories Bank no later than (insert date). 62 Statement of mission objectives: Computer- 5. Assess training needs (trainees, trainers, type based information and telecommunications of training, cost). system 6. Assess the cost of a NCD and risk factor sur- (Name of consultant) will be responsible for: veillance system. 1. Establishment of computer-based telecommu- nications system at national, state and local 7. Assess the need for sentinel sites or periodic levels, and possibly in other areas to routinely surveys, and develop a strategy for implemen- collect, analyze, and disseminate surveillance tation. data; to rapidly communicate messages; and 8. Propose terms of reference for additional work to assist in the investigation of epidemics, in- you may find necessary. cluding needs for software, hardware, data transmission, and data outputs. Written output: A short report summarizing your 2. Confidentiality issues should be addressed, as findings and recommendations, remitted to the Bank well as systems’ management. (Should they no later than (insert date). be internal or contracted?) Statement of mission objectives: Economic 3. Define a standardized system for laboratory analysis data to be used in national reference labora- (Name of consultant) will collect the data necessary tories and in state laboratories. This system to undertake the economic analysis and write a first should address needs for communicable and draft of the economic analysis that will consist of noncommunicable diseases. the following: 4. Define training needs, develop implementa- 1. A cost-effectiveness analysis whose purpose tion program, and estimate cost. would be to examine the potential impact of the surveillance system on the incidence or Written output: Produce a short report (bullet points) prevalence of each notifiable disease. This for the client, summarizing findings during mission analysis would yield a map of the burden of and a full report no later than 8 days after the mission. diseases in the country and help determine where to orient surveillance efforts. Statement of mission objectives: Noncommu- 2. An equity analysis which would attempt to nicable diseases and risk factor surveillance investigate the equity implications of the sur- (Name of consultant) will: veillance system—in other words, who would 1. In keeping with project objectives, review the benefit most from the project? project proposal regarding chronic diseases and risk factors surveillance. 3. A sustainability analysis that would address three questions: (a) Will there be sufficient 2. In collaboration with the project team, select counterpart funding for the project? (b) What the health conditions for surveillance. are the additional recurrent costs that will be 3. Recommend the most appropriate type of sur- generated by the project and who (that is, what veillance (sentinel, survey, or other) for the level of government) will pay for them? (c) Is conditions or risk factors selected. there reason to believe that these entities will be able to afford this additional financial bur- 4. Review the recording and reporting forms. den? 63 APPENDIX B.3 SAMPLE TERMS OF REFERENCE FOR SPECIALISTS PARTICIPATING IN PREPARATION MISSIONS 4. A risk analysis to test the robustness of the Written output: A short report (bullet points) regard- cost-effectiveness and sustainability analy- ing findings during the mission to appendix to the ses to reasonable changes in the key aide memoire, and a draft economic analysis no later parameters. than (insert date). 64 APPENDIX B.4 Specific Disease Surveillance “Tips” Box 9 BEHAVIORAL RISK FACTOR SURVEILLANCE Why are behaviors and noncommunicable What is behavioral risk factor surveillance? diseases important? Surveillance of BRFs is essential to plan and evaluate programs Most countries of the world have undergone, or are undergoing, that aim to prevent NCDs and injuries. BRF surveillance provides an epidemiologic transition with the burden of disease now evidence about whether programs are having the desired impact primarily due to NCDs and injuries, not communicable diseases. of reducing risky behaviors and promoting healthy lifestyles. BRF In developing countries these changes place costly demands on surveillance in developing countries usually begins as a series of the health sector because NCDs often require highly technical, household surveys that include, at a minimum, questions expensive interventions and specialist care. The key to averting regarding smoking, physical activity, alcohol use, and diet. Other or controlling this global NCD epidemic is primary prevention. topics include injury prevention, preventive health-seeking behaviors, mental health, sexual behaviors, and self-report questions on weight, height, and diabetes. In more developed How can NCDs be prevented? surveillance systems BRF surveillance is continuous (such as The most common NCDs (diabetes, hypertension, coronary artery ongoing phone surveys). This permits time-linked analyses that diseases, some cancers, and injuries) are largely preventable with are more useful in assessing the impact of specific interventions changes in lifestyle and behaviors. Important BRFs for NCDs and events on behaviors. include: cigarette smoking, obesity, lack of physical activity, high dietary fat intake, and substance abuse. There is incontrovertible Are behaviors important only for evidence that by modifying these risk factors NCDs can be noncommunicable diseases? prevented. Unintentional injuries due to traffic accidents are a leading cause of death, particularly among young adults. Many Behaviors and lifestyle contribute not only to the occurrence of traffic injuries and deaths can be avoided by using seat belts in NCDs, but to the occurrence of communicable diseases as well. cars, and helmets while riding on motorcycles and bicycles. Other Changing sexual behavior and condom use is essential to preventive behaviors are related to the utilization of health preventing STIs, including HIV/AIDS. Hand-washing is key to services; an example is Pap smears to screen for cervical cancer preventing transmission of diarrheal diseases, intestinal parasites, can lead to early diagnosis and cure. Information about the hepatitis, and skin infections. BRF surveillance often includes prevalence of these behaviors is vital to making health questions related to these behaviors. promotion and disease prevention programs more effective. What are youth surveys? It is very important to focus prevention activities on youth, a time in life when risky behaviors often begin. Thus there are BRF surveys that focus specifically on young people. Youth surveys are usually carried out confidentially in schools. 65 APPENDIX B.4 SPECIFIC DISEASE SURVEILLANCE “TIPS” Box 10 HIV/AIDS SURVEILLANCE What conditions should be reported? • Underreporting may occur, especially in areas where HIV testing, health care, and resources are limited. Using • HIV infection, AIDS active case findings may enhance surveillance in these • Deaths in persons with AIDS and HIV infection areas. Standard case definitions need to be addressed. Several public • Dissemination of data to public health decisionmakers health organizations (the WHO, the PAHO, CDC) have established and back to the persons who reported the cases can case definitions that can be used. help foster recognition of the importance and utility of HIV/AIDS surveillance. What information should be collected on these What other sources of data may be useful in persons? describing the HIV epidemic? A standard set of data should be collected using a standardized Data from HIV/AIDS surveillance should be interpreted with other report form for all cases that meet the reporting criteria, including: available data for a more comprehensive picture of the HIV (a) personal identifier, (b) date of diagnosis, (c) basic demographic epidemic, such as (a) other surveillance systems (for instance, STI information, (d) place of residence, (e) risk behaviors, (f) opportu- surveillance); (b) HIV serosurveys (in antenatal or STI clinics); and nistic conditions, and (g) date of death. The data elements (c) vital statistics registries. collected should be limited to those that will be routinely used for public health action. The simpler and shorter the case report form, What is the role of HIV serosurveys the more likely it is that cases will be reported completely and quickly. (HIV sentinel surveillance) in describing the status of a country’s HIV epidemic? Who should report? Population-based prevalence surveys are the most useful but may Hospitals, health-care workers who work in hospitals, private be difficult to undertake. Instead of those surveys, serosurveys of doctors, clinics, community health workers, and laboratories that pregnant women in antenatal clinics most closely approximate the perform HIV testing. Local laws can require these persons to prevalence levels in the adult population (although the relation- report cases to health authorities. Health authorities may also ship between prevalence among clinic attendees and that of the actively contact health-care providers and institutions to ensure general population remains uncertain). that all cases are reported. High-quality sentinel surveillance systems have frequent and timely data collection, conduct surveillance in appropriate How should they report? populations, are consistent in the sites and groups that are There are many options for reporting, including mail, telephone, measured over time, and provide estimates that are representative fax, e-mail, or through the Internet, if security can be main- of the population. tained. What are some of the key factors in a successful HIV/AIDS surveillance system? • Strict confidentiality must be maintained in order for the system to remain acceptable to the community and providers. 66 Box 11 SURVEILLANCE IN TUBERCULOSIS CONTROL TB is a global public health threat. In the absence of treatment, Treatment the infectious disease can kill 50 percent of those who fall ill within two to five years. The epidemic is worsening where The TB treatment register enables proper case management. TB economic and social crises and the HIV/AIDS epidemic are treatment entails six to eight months of multi-drug therapy, with raging. Persons with compromised immune systems are at high observation during at least the first two months, for new TB cases. risk of infection and illness. The control of TB depends on the Smear exams at two, five, and six to eight months are used to early detection and treatment of persons with infectious disease. monitor treatment progress, and outcomes are recorded: cured This forms the core of the directly observed treatment (DOTS) (smear-negative); treatment completed (without final smear); lost strategy recommended by the WHO, the World Bank, and other for view; died; treatment failed; or transferred. Retreatment cases partners. See http://www.worldbank.org/TB for further informa- are monitored in a similar fashion, with drug susceptibility testing if tion and other links. Su illance methods and several computer- available. Quarterly reports on treatment results are developed, ized reporting tools are available suitable for the capacity of usually at the local level. These reports enable examination of different public health systems, and can form a part of an problems and progress in quality or access to services, and assist in integrated surveillance system (see the WHO’s EPI-TB and CDC’s tracking the epidemic and control efforts at state, national, and BOTUSA models). international levels. Global targets have been set for 2005 of: 70 percent detection of infectious patients and 85 percent cure rates Case detection of those treated. Sputum smear microscopy is the preferred cost-effective method Surveys to measure drug-resistant TB, HIV-TB, and of diagnosing infectious TB patients. In some countries registers trends in TB infection and prevalence of all respiratory symptomatics (those who have had a cough for two to three weeks) presenting at health services are kept, and Additional surveillance tools are used in TB epidemiology and are useful in determining whether all are referred for smear control. These include: (a) representative national surveys of drug- exams. Laboratory registers record all examined patients and resistant TB; (b) surveillance of HIV-infection among registered TB results, which are then included in a TB treatment register. patients and TB illness or infection among HIV-infected persons; (c) Assignment of proper case definitions are critical: new sputum- periodic population-based surveys (too costly for most low-income smear positive, sputum smear-negative, or extrapulmonary; countries) to determine TB prevalence and incidence levels; (d) risk of relapse; or retreatment ( which includes cases returning after TB infection surveys to estimate trends in incidence based on default and previous treatment failures). Laboratory networks infection levels in schoolchildren or other subpopulations. Where are formed to enable regular quality control of smear-microscopy routine death registration is operating, examinations of trends in and access to supplementary diagnostic tools. Quarterly reported TB mortality is useful. Investigations of TB outbreaks are reporting on new TB cases, by case category, and with age and more feasible in low-incidence countries or in subpopulations in sex disaggregation for smear-positive patients is recommended. higher-burden countries (prisons, hospitals, and so on). See: http://www.who.int for the annual WHO reports on the global TB epidemic. 67 APPENDIX B.4 SPECIFIC DISEASE SURVEILLANCE “TIPS” Box 12 MALARIA SURVEILLANCE 1. The burden of malaria is heaviest in remote rural areas, which (a) Counting only definitively diagnosed cases greatly are often beyond the reach of health facilities. As many as 80 underestimates disease burden. Cases diagnosed on percent of malaria cases and deaths are managed without the clinical grounds should also be included in case counts; patient ever accessing public health facilities. Of those who do reporting should not be limited to facilities with seek care within the public health system, the vast majority will capability for definitive diagnosis. be managed at the periphery of the system. As a result, (b) Because cases may be diagnosed by multiple methods, traditional public health facility–based surveillance systems clear case definitions are required. These vary by the will only detect a small fraction of malaria cases and deaths; transmission intensity of the region. In Sub-Saharan these data are rarely used for planning or monitoring control Africa the definition of a clinical case often includes programs. Therefore: anyone with a recent fever history or measured (a) Assess whether investments in routine surveillance temperature of more than 37.5° Centigrade. In other systems are warranted, particularly in regions (Sub- regions patients with fever may only be considered a Saharan Africa) where reporting infrastructure is not malaria case if there is no other explanation for their well developed. Support instead might be directed illness. Care should be taken to not double-count cases toward development or strengthening methods for diagnosed in both clinics and laboratories. collection of household level data, such as the Demo- 3. Regardless of the method chosen, surveillance data, in general, graphic and Health Surveys (DHSs) or Demographic will greatly underestimate overall disease burden. In addition, Surveillance Systems, which provide better estimates of malaria disease burden will vary with the seasons and from disease burden. year to year based on changes in weather patterns. Interpreta- (b) Sentinel surveillance, using a small number of sites for tion of routine malaria surveillance data, therefore, should be monitoring malaria cases, has been used in some based on trends, not absolute numbers, comparing case countries. One advantage of this approach is that one information with similar months over several years. can better link changes in disease burden to specific 4. There are four species of Plasmodium that cause clinical interventions and investigations (such as entomologic malaria in humans. Plasmodium vivax is more common in Asia studies). and the Americas and P. falciparum (the species responsible (c) If investments in routine surveillance are warranted, all for almost all malaria associated deaths) causes more than 90 levels of the public health system must be involved in percent of cases in Sub-Saharan Africa. The other two species, reporting malaria cases. Methods to include private P. malariae and P. ovale, are of little public health importance. sector providers (including pharmacies and drug sellers) Laboratory testing is the only method for determining species. in case reporting should also be explored. The importance of differentiating these species for surveillance purposes must be weighed against the costs of laboratory 2. In almost all countries where malaria is endemic cases will be testing and the additional burdens placed on data collectors. diagnosed both by definitive methods (microscopy or rapid As a general rule, surveillance systems in Sub-Saharan Africa diagnostic tests) and by clinical findings. Definitive diagnostic do not differentiate cases by species. methods are more widely available in Latin America and Asia than in Sub-Saharan Africa, but are rarely available in peripheral health facilities in any region. Therefore: 68 Box 13 VITAL STATISTICS AND SURVEILLANCE OF THE MILLENNIUM DEVELOPMENT GOALS: INFANT AND MATERNAL MORTALITY What are vital statistics? How is maternal mortality measured? The measurement of vital events is “the single most important The MMR is the number of maternal deaths (deaths during addition that developing countries can make to their existing pregnancy, childbirth, or the puerperium that are due to the surveillance system” (White and McDonnel 2000). Knowledge of pregnancy or its management) per 100,000 live births. Measure- levels, causes, and trends in mortality is fundamental to public ment of maternal mortality has been an issue for many years and health practice, and guides a country’s public health priorities. A is not easily carried out even using household surveys. This vital registration system, using birth and death certificates, permits highlights the need for identification of maternal deaths and their the reporting of key vital statistics such as the infant and maternal causes through improved death certification. mortality rates (IMRs and MMRs). How is infant and maternal mortality surveil- What are Millennium Development Goals? lance carried out? The MDGs were established by the international community as a Reporting of IMR and MMR alone permits targeting areas with roadmap for an expanded vision of development (http://sima/ higher mortality rates. However, in order to focus resources more mdg). The MDGs are a focal point of the Bank Group’s strategic efficiently and reduce mortality rates more quickly, information framework. Health-related MDGs include the reduction of under- about why women and infants are dying is needed. This is done five child mortality by two-thirds, and the reduction of maternal through case investigations, or audits, that include information mortality by three-quarters between 1990 and 2015. The IMR and about events leading up to the death, whether proper care was the MMR are indicators for these MDGs. obtained, whether there were economic, cultural, geographic, or other barriers to care, and so on. How is infant mortality measured and what is its importance at the local level? What are obstacles and incentives to improving The registration of births and deaths provides an accurate and vital statistics? timely measurement of IMR (number of infant deaths [under 1year Infant and maternal mortality surveillances are easier with a vital of age] per 1,000 live births). The international community has registration system. While coverage of death certification in low- depended on household surveys (such as DHS) to estimate IMR. income countries is often poor, it varies widely and is not While these estimates may be accurate, they are not timely, necessarily related to gross domestic product. Obstacles to death representing a period five years prior to the survey, and quoted for and birth certification, such as fees, should be eliminated. Health years after. Furthermore, while surveys provide national, and facilities should provide birth and death certificates prior to sometimes regional estimates, they are rarely useful at an discharge, rather than demand that people go to a special office to operational level (at the level of the state or municipality). Health obtain those certifications. Local health-care providers can certify systems are increasingly decentralized, requiring local assessments births and deaths in the community. Examples of incentives of IMRs. The need to focus scarce resources in areas with poorer include the requirement of a death certificate for burial or to health outcomes also argues for improved vital statistics at the receive any inheritance. When building a system, vital registration local level. can begin in small sentinel areas, and expand as it is evaluated and improved. Proposed Intermediate indicators for health MDGs can be found at: http://wbln0023/Networks/HD/HDdocs.nsf/Thematic+Group+Documents/All/ By+Author/9FF92329E0A0EB5A85256B1300776723?OpenDocument 69 Box 14 AVIAN AND HUMAN INFLUENZA SURVEILLANCE What is influenza? 1. An early warning system that can detect human clusters of severe pneumonia and lead to rapid contain- Influenza is caused by a virus that is spread from person to ment of new cases should be developed in every country. Even person primarily via respiratory droplets. Most people who are in low resource settings, surveillance for clusters of deaths infected with influenza viruses will have mild respiratory and from pneumonia in health care settings can be implemented constitutional symptoms such as fever, cough, congestion, and such deaths quickly reported. At a bare minimum, clusters fatigue, and muscle aches. Nevertheless, influenza can cause of deaths among hospital workers should be reported severe disease requiring hospitalization and sometimes death. immediately. A rapid response team is needed to assist in The influenza virus is constantly evolving, requiring the investigating such clusters, and to swiftly begin containment production of a new vaccine each year that will provide interventions where appropriate. Ideally, communities should protection against the latest circulating virus strains. be involved in reporting unusual numbers of severe pneumonia or unexplained deaths (rumor registers). However, community What is avian influenza and why the concern reporting may be difficult to implement on a large scale. about a pandemic? 2. Every country should also have a system for identifying and investigating poultry die-offs. In the pre-pandemic Avian influenza refers to a variety of influenza viruses that stage it is very important to work closely with animal control primarily affect birds, but on rare occasions may infect other authorities and identify influenza outbreaks in bird and poultry species including pigs and humans. Since 1997, more than 120 in order to contain its spread and limit contact between cases of human avian influenza infections have been docu- infected birds and humans. This will reduce opportunities for mented caused by an influenza A(H5N1) subtype, with mortality human infection, thus decreasing the likelihood that the virus rates of around 60%. The vast majority of cases have been will adapt for human-to-human transmission. Any outbreak in among people who were in close contact with infected birds. A birds should also lead to an active search for human cases. major concern is that the H5N1 virus may adapt into a strain that is easily transmitted from human to human. This could 3. Finally a virologic surveillance system should be cause a global influenza pandemic. The possibility of such a implemented. Most countries, even those in low resource mutation and new strain developing will persist as long as the settings, have at least one laboratory with the potential for virus continues to circulate in birds that have contact with identifying viral types. Many countries have a network of humans - a situation which should endure for years to come. The laboratories. The system should monitor circulating influenza world is considered to be in a pre-pandemic stage. strains and reliably confirming whether the H5N1 sub-type is present, either in birds or humans. If a country has no What surveillance activities are important in a laboratory, then arrangements should be made for confirming or discarding H5N1 by using laboratories in neighboring pre-pandemic situation? countries. The virus is highly pathogenic and laboratory bio- Surveillance during the pre-pandemic phase is more important safety is an issue. than surveillance when a pandemic is underway. The greatest opportunity for preventing or delaying national and international spread occurs in the pre-pandemic phase when numbers are What are examples of prevention and small and containment may still be possible. Resource-intensive containment activities carried out in the activities, such as animal surveillance and the active detection, investigation and laboratory confirmation of human cases are pre-pandemic phase? vital pre-pandemic, but are neither sustainable nor a priority A primary objective is to reduce opportunities for human infection. once a pandemic occurs. Multidisciplinary rapid response teams should be available to investigate poultry die-offs and human severe pneumonia clusters. Surveillance during a pre-pandemic is needed to detect the Identification and culling of infected or exposed poultry limits their transition to efficient and sustained human to human transmis- contact with humans. If human to human transmission is sion, carry out effective prevention and containment activities, suspected, measures to limit contact among humans such as and monitor circulating viral strains. Ideally, it is integrated quarantines, closing schools and workplaces and limiting travel to within an existing public health surveillance system. Three types and from affected areas may help delay spread. Protective gear of surveillance are important: should be provided to health workers. Vaccine development could Much of this information comes from the WHO AI website (http://www.who.int/csr/disease/avian_influenza/en/), a very useful resource. 70 AVIAN AND HUMAN INFLUENZA SURVEILLANCE (CONTINUED) be very effective in limiting the spread, however vaccine may cause pandemics. WHO has a global network called Flu-Net. production usually takes several months after a new strain is It consists of 112 National Influenza Centers (NICs) in 83 countries identified. Anti-viral drugs may help decrease severe illness and that monitor influenza activity and isolate influenza viruses. These death. Their mass use for prophylaxis is being discussed. Finally, NICs also report the emergence of “unusual” influenza viruses1 it is necessary to communicate effectively with the public about that could be decisive for mounting a timely response to risk and protection. pandemics. The NICs send viral specimens to four WHO Collaborat- ing Centers that carry out virus gene sequencing. Based on this How is routine surveillance for seasonal influ- system, every year WHO predicts the most likely strains to circulate. Influenza vaccines are updated semi-annually based on enza done? these predictions. In high income, and some middle income countries, routine influenza surveillance is carried out by monitoring people with How are countries preparing for a pandemic? flu-like illnesses, hospitalizations for flu, and via laboratory- based viral surveillance. Usually sentinel sites scattered Most countries have elaborated a pandemic preparedness plan throughout a country’s health care system report the number of that addresses the need for an adequate system for alert, response people with flu-like symptoms. Ideally, the sites also systemati- and disaster management. Depending on available resources, cally test for influenza by collecting nasal or throat swabs and more specific preparations are made, such as stockpiling of sending them to labs for viral typing. In addition, public health antivirals, strengthening risk communications, investing in laboratories report trends in viral sub-types being isolated. This pandemic vaccine research and promoting domestic production of information is tracked by health departments and helps guide influenza vaccines. One component of such a plan should be to the care health workers provide. In addition to identifying the strengthen the capacity to respond to yearly epidemics of start of influenza outbreaks, these surveillance systems can influenza. A surveillance network for human and animal influenza detect unusual influenza strains. Implementing or enhancing and a targeted influenza vaccination program are the cornerstones seasonal influenza surveillance in as many countries as possible of a national influenza policy. The challenge now is to implement is important for pandemic preparation. the plans. How is seasonal influenza controlled? Vaccination is a key component of influenza control. Recommen- dations about who to vaccinate differ depending on a country’s Is a new flu due? resources. Most high and some middle income countries target Major flu pandemics, 1750–2005 specific groups of people at high risk of severe influenza- associated disease. Health communication and education about Scope and severity individual protective strategies can also contribute to reduce the spread of influenza. What is global influenza surveillance and why is it important? Continuous global surveillance of influenza is key for preparing annual vaccines and for identifying new or unusual strains that 1750 1775 1800 1825 1850 1875 1900 1925 1950 1975 2000 1 According to the new International Health Regulations (IHR-2005) influenza A caused by a new viral subtype must be reported immediately to the WHO. For further information, please visit: http://www.who.int/csr/resources/publications/influenza/WHO_CDS_CSR_GIP_2005_8/en/index.html (Recommended strategic actions) http://www.who.int/csr/disease/avian_influenza/consultation/en/index.html (Priority public health interventions) 71 72 APPENDIX B.5 The Who STEPwise Approach To Risk Factor Surveillance T he growing burden of NCD represents a major challenge to health development (Bonita and others 2001). The WHO has responded by giving The STEPwise approach encourages the develop- ment of an increasingly comprehensive and complex surveillance system depending on local needs. The higher priority to NCD prevention, control, and sur- WHO emphasizes that, for surveillance to be sus- veillance. The WHO STEPwise approach to risk tainable, small amounts of good quality data are factor surveillance (STEPS) is the WHO-recom- more valuable than large amounts of poor quality mended NCD surveillance tool. The WHO is building data. one common approach to defining core variables for surveys, surveillance, and monitoring instruments. Countries take the first step by adopting a core of The goal is to achieve data comparability over time standardized questions regarding behaviors includ- and among countries. STEPS offers an entry point ing socioeconomic data, tobacco and alcohol use, for low- and middle-income countries to get started physical inactivity, and nutrition. Questions that in NCD activities. It is a simplified approach provid- form the core data for each of these areas are simple ing standardized materials and methods as part of and few—and ensure international comparability. technical collaboration with countries, especially Expansion of the basic questions is possible depend- those that lack resources. ing on local needs and resources. Optional modules on other behaviors can be incorporated. Figure 2 The WHO’s STEPwise Approach Once step 1 is in place countries can build on it: more complex data can be added sequentially as resources allow. The core of step 2 includes physical measures of blood pressure, height, and weight. Step 3 involves blood sampling; the core includes blood glucose and cholesterol. Steps implementation at the country level is strategic and coordinated, builds capacity, and is sustainable. The content of the WHO STEPS document is avail- able on the Internet at: http://www.who.int/ncd/ surveillance/surveillance_publications.htm. 73 74 APPENDIX B.6 Surveillance Processes and Task by Level Figure 3 Surveillance Processes and Task by Level Primary data collection, case reporting Limited data analysis Local Local Local Local Local Local Outbreak detection/investigation Local level Level Level Level Level Level Level Treat/implement public health intervention Report Data collection Technical assistance to local level State State State/Provincial Report Information feedback to local level Data Analysis Technical expertise an support Analytic studies National Confirmation of cases Ministry of Health Planning and funding Feedback 75 76 APPENDIX B.7 Surveillance Glossary Active case finding The dynamic identification of the occurrence of a disease or health event under surveillance (for example, house visits by community workers to identify cases of TB). Active surveillance The dynamic seeking of data from participants in the surveillance sys- tem on a regular basis. Aggregate surveillance The surveillance of a disease or health event by collecting summary data on groups of cases. In many general practice surveillance schemes clinicians are asked to report the number of cases of a specified dis- eases seen over a period of time. Attack rate The proportion of those exposed to an infectious agent who become (clinically) ill. Carrier A person who harbors a pathogen and can transmit it but has no clini- cal signs of infection. In epidemiological investigation we depend on the use of case definitions. Definition may be based on clinical or labo- ratory criteria. We may also allow for gradations in the likelihood of being a case (definite, probable, possible). This is particularly useful when the pathogen is unknown. Case A person who meets the case definition. The definition of a case will depend on what one is trying to describe. Infection can be clinical or subclinical. Both types of infection can lead to a carrier state. Case-based surveillance The surveillance of a disease by collecting specific data on each case ( reporting of details on each case of AFP). Case-fatality ratio The proportion of people who die as a proportion of all cases. This will vary depending on the case definition used. Cluster The occurrence of an unusual number of cases in persons, places, or time. 77 APPENDIX B.7 SURVEILLANCE GLOSSARY Community surveillance Surveillance where the starting point is a health event occurring in the community and reported by a community worker or actively sought by investigators. This may be particularly useful during an outbreak and where syndromic case definitions can be used. The active identi- fication of community cases of Ebola virus infection in Kikwit, is an example of this type of surveillance. Comprehensive surveillance Surveillance of a specified disease or health event in the whole popu- lation at risk for that event (an example is AFP surveillance). Contact An individual who has had contact with a case in a way that is consid- ered to cause significant exposure and therefore risk of infection. Due dates The dates by which reports from a specified period should be received by each level of the surveillance system (sed to calculate timeliness). Endemic The constant presence of a disease within a given geographic area or population group. Enhanced surveillance The collection of additional data on cases reported under routine sur- veillance. Routine surveillance is a starting point for more specific data collection on a given health event. Epidemic The occurrence of cases of an illness clearly in excess of expectancy. This is often referred to as an outbreak (more neutral). Endemic dis- eases are those that exist at higher rates over a prolonged period. Epidemiological case definition The definition of a case used for reporting to the surveillance system. The definition may be clinical, laboratory, or both. It may relate to a specified disease (such as measles or yellow fever) or may identify a syndrome (for example, meningitis or AFP). Exception flagging system The existence of an automated system of data analysis that calculates thresholds for unusual events or exceptions. Exposed Someone who has met with an infectious agent in a way that may cause disease. Feedback The regular process of sending analyses and surveillance reports on the surveillance data back through all levels of the surveillance system so that all participants are informed of trends and performance. Health event Any event relating to the health of an individual (such as the occur- rence of a specific disease or syndrome, the administration of a vaccine, or a hospital admission). Hospital surveillance Surveillance where the starting point for a report is the admission to a hospital of a patient with a particular disease or syndrome. Incidence The number of persons who fall ill with a certain disease during a defined time. 78 Infectious disease An illness due to a specific infectious agent or its toxic products that arises through transmission of that agent or its products from an in- fected person, animal, or reservoir to a susceptible host, either directly or indirectly through an intermediate plant or animal host vector, or inanimate environment. Integrated surveillance Common approach that provides a universal surveillance service us- ing similar structures and techniques. Intensified surveillance The upgrading from a passive to an active surveillance system for a specified reason and period (usually because of an outbreak). The sys- tem becomes more sensitive and secular trends need to be interpreted carefully. Laboratory surveillance Surveillance where the starting point is the identification or isolation of a particular organism in a laboratory (for example, surveillance of salmonellosis). Mandatory surveillance A surveillance where participants must report to the system. Notifi- able diseases are one example of a mandatory system where reporting is mandated by law. In another example, health authorities may re- quire that all public laboratories report specified diseases. This is usually not by law, but is linked to their contractual duties. Notifiable disease A disease that must be reported to the authorities by law or ministe- rial decree. Outbreak The occurrence of two or more linked cases of a communicable dis- ease. Passive surveillance Surveillance where reports are awaited and no attempt made to ac- tively seek reports from the participants in the system. Performance indicators Specific agreed-on measurements of how participants are function- ing within the surveillance system. These indicators may measure both the process of reporting, action taken in response to surveillance in- formation, and the impact of surveillance on the disease or syndrome in question. Periodicity The presence of a repeating pattern of excess cases. The repeater pe- riod can be in years, months, or weeks. Prevalence The number of persons who have a disease at a specific time Primary care surveillance Surveillance where the staring point for a report is a new consultation for a particular disease or syndrome with a primary care physician or health worker at a clinic. Reporting completeness Proportion of all expected reports that were actually received (usually stated as percent completeness as of a certain date). 79 APPENDIX B.7 SURVEILLANCE GLOSSARY Reporting system The specific process by which diseases or health events are reported. This will depend on the importance of the disease and the type of surveillance. Reporting timeliness Proportion of all expected reports that were received by a certain due date. Routine surveillance The regular systematic collection of specified data in order to monitor a disease or health event. Sentinel surveillance The surveillance of a specified health event in a sample of the popula- tion at risk. The sample should be representative of the total population at risk. Surveillance The systematic collection, collation, and analysis of data and the dis- semination of information to those who need to know so that action may be taken. Surveillance predictive value The likelihood that an “ outbreak “ detected by a surveillance system is truly an outbreak. Surveillance report A regular publication with specific information on the disease under surveillance. It should contain updates of standard tables and graphs as well as information on outbreaks, and so on. In addition it may contain information on the performance of participants using agreed- on performance indicators. Surveillance sensitivity The ability of a surveillance system to detect an outbreak (the propor- tion of all outbreaks that could be detected by the system). Survey An investigation in which information is collected systematically. It is usually carried out in a sample of a defined population group and in a defined time. Unlike surveillance, it is not ongoing, although it may be repeated. If repeated regularly, surveys can form the basis of a sur- veillance system. Unusual event The occurrence of a disease or health in excess of expectations. This expectation is either a static or dynamic threshold set by the system. Voluntary surveillance A surveillance system wherein participants take part and report vol- untarily. Zero reporting The reporting of zero cases when the participant has detected no cases. 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The toolkit also makes use of WHO references, primarily those from the WHO’s Web site. Part A of this toolkit provides some theoretical concepts, and knowledge about surveillance that has been gained through applying these concepts and the practice of surveillance in developing countries. Part B provides information that will be useful to Task Managers as they prepare loans for strengthening public health surveillance systems. Several World Bank experiences are shared. The focus of part B is on practical aspects of surveillance and on lessons learned.