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5.2 Information systems and community diagnosis in developing countries*

5.2 Information systems and community diagnosis in developing countries*
Oxford Textbook of Public Health

5.2
Information systems and community diagnosis in developing countries*

Chitr Sitthi-Amorn

Outline
Introduction
The objectives of public health actions

Improving average health status and reducing the burden of illnesses

Reducing health inequities

Responding to the legitimate expectations of individuals

Improving the efficiency of health system

Protecting individuals and enhancing fairness
Components of information systems for planning health care

The measurement of needs

Information about the organization and financing of a health service

Resource allocation and utilization of services

Health system performance

Information on health outcomes

Information of development policies affecting health
The general framework for community diagnosis

Defining the community

Health indicators

Sources of information and the methods that can be used for community diagnosis

Trend analysis

Characteristics of community diagnosis

Sources of information and methods for community diagnosis
Technological limitations of information systems and community diagnosis

Estimates of lifetime effects on individuals with particular health problems

Effects of health problems of individuals on their relatives
Information systems of developed and developing countries
Chapter References

Outline
This chapter outlines the importance of information in the planning, monitoring, and evaluation of health problems, their determinants, intervention options, and evaluation of health intervention in a community. It argues for at least five objectives of the health actions, which determine what types of information are needed. A general framework for information and community diagnosis is given which includes defining the community, agreeing on the indicators, determining the sources and methods of obtaining the information, and using the information to predict the current situation as well as future trends. Each of the sources or methods used for information gathering (routine reports, surveillance, survey and special studies, rapid survey, contact tracing, and vital registration and census) has inherent strengths and weaknesses. Therefore a combination of approaches for collecting information for community diagnosis is necessary. Despite the availability of several approaches to developing an information system, some technological limitations for a community diagnosis exist and are also discussed. Finally, a comparison is made between information systems in developed and developing countries, which partly reflect the different emphasis in the operation of health-care systems as well as differences in available resources for community diagnosis.
Introduction
Information is the basis for planning for a rational allocation of resources to cope with public health problems. Information should shed light on health situations, help to set priorities, appraise options, develop and implement programmes, and monitor and evaluate actions to determine whether they adequately address the situations. Information is the essence of the planning process. Decision-makers balance evidence from information with their values and the imperatives to arrive at the best choices. Information includes what is measured, what is not measured, and what is inherently unmeasurable. Most information systems, which rely on information technology, collect measurable quantifiable information possibly at the expense of less explicit soft and qualitative information. Therefore, an appropriate mix of measurable and intangible information will be needed. Although the information is rarely perfectly accurate, its accuracy can be enhanced through the development of a clear operational definition, training and motivating the enumerators, and interaction with stakeholders to standardize interpretations.
The definition of a community can have many interpretations such as a neighbourhood or a collection of people in similar geographical circumstances. A community also refers to a group of people who share the same stakes and common interests such as trade unions, those who are mobilized around a given activity, or the users of health services. Some have even expanded the definition of a community to include those employed in a workplace, the population of a nation, or a civil society. In this chapter, a community can encompass several interpretations such as a village, subdistrict, district, province, or nation. A fundamental requirement of an information system is to enhance the ability of decision-makers to employ evidence-based actions and enhance their roles in solving problems of a community however defined. A community is not a static entity; therefore any meaningful information system for the diagnosis of community problems requires a dynamic interaction between the members of the community and the managers of information systems. It is important to make the best use of updated information and interpret information into meaningful strategic options that reflect the reality of health and health-care systems in a given community or society. Any information produced should then be fed back to the community to enhance their future involvement. This feedback can then be the driving force in linking information to actions because the community will press for the kind of information they can use.
Public health policy-makers and health-care managers need timely, useful, and balanced information (quantifiable and intangible) for the diagnosis of health needs, their determinants, and trends to achieve effective planning and monitoring of health-care interventions. New challenges to public health have highlighted the importance of community involvement in defining problems and in coping with them. These challenges include globalization and its impacts on environment, the relationship between trade and health, emerging diseases, the market orientation of health-care system, and changes in behaviour and lifestyles. There are several ways to obtain health information for the diagnosis of communities including routine health facility reporting, screening, surveillance, special large-scale surveys, rapid surveys, contact tracing, and census. These methods vary depending on the objectives, investment, and utilities available.
The objectives of public health actions
An overall objective of community diagnosis is to estimate the magnitude of the health problems and their determinants as well as to analyse trends and changing paradigms of these problems and determinants. Because the community consists of heterogeneous groups, the overall objective needs to be expanded to include many value-laden issues such as health needs and determinants, equity, responsiveness to expectation, efficiency, protection of individuals, and fairness. The results of community diagnosis can then be used as evidence for discussion among the stakeholders in the community, balancing the values of the various stakeholders in setting priorities and making decisions for resource allocation acceptable to the community. The priorities and decisions for control should take into account not only the current status of health but also the impact that controls may have on health of the future generation.
The priorities and decisions for control depend not only on the indicators used for the diagnosis but also on the expressed or unexpressed values of a health system. Recently, the World Health Organization (WHO) suggested some possible value-laden objectives of a health system. Indicators for these value-laden objectives are being developed for better measurements of how well a health system has achieved its objectives. The possible value-laden objectives of a health system include (a) improving average health status and reducing the burden of illnesses, (b) reducing health inequities, (c) responding to the legitimate expectations of individuals, (d) improving the efficiency of health system, and (e) protecting individuals and enhancing fairness (WHO 2000a).
Improving average health status and reducing the burden of illnesses
Improving average health status and reducing the burden of illnesses as measured by life expectancy, death rates by age groups, disease or morbidity rates, and the measurement of the burden of illness combining mortality and morbidity are important functions of public health professionals. Indicators for the measurement of risk factors to explain mortality and morbidity have also been developed.
There are changes occurring in the burden of illnesses resulting from population growth both in developing and developed countries. In addition, demographic and epidemiological transitions can influence trends of ill health in a nation or community. Lifestyle changes are associated with illnesses such as cardiovascular diseases and the epidemics of HIV infection and tobacco use. Owing to globalization, there are many things in the future that will change health and the burden of illnesses in a community. The current decline in communicable disease mortality in many areas of the world may reverse due to drug resistance and new pathogens. Therefore, the mortality and morbidity rates from various diseases will be the backbone of information needed for health planning.
Reducing health inequities
Equity is particularly important if planning involves allocation of resources for health from the government budget that comes mainly from taxation. The agencies implementing the plans can be the government or non-governmental organizations supported by the government. In contrast, the private health system does have more responsibility to satisfy individuals who pay for their services, rather than the responsibility for reducing inequities. Therefore, the reduction of health inequities as an indicator does not apply to the private as much as to the government system.
Health inequality is linked to the agenda of poverty and material deprivation. The WHO has developed a set of measures for health inequalities including social, household, and individual differences in health. For example, male life expectancy differs greatly among various regions of the United States. Health inequalities differ between various regions of the world with different stages of human development as exemplified by the health status in Mexico compared with that of the United States and Japan. The distribution of life expectancy at birth estimated from large numbers of small area studies showed that life expectancy is most equally distributed in Japan. In both Mexico and the United States, the distribution of life expectancy between areas was wider, indicating more inequity between population groups. The inequity is particularly significant for men (WHO 2000a) Measuring inequalities gives health a central theme in the development agenda.
In terms of investment in research, there is also a 10/90 disequilibrium between global health expenditures for research and the burden of illness (Commission on Health Research for Development 1990). This report found that less than 10 per cent of global health research funds were spent on 90 per cent of health problems in developing countries. Thus, information on these parameters will be needed to plan a more balanced allocation of resources according to need.
Responding to the legitimate expectations of individuals
The legitimate expectations of individuals reflect an attempt to fulfil their right to health services because they are citizens of a country and community. Legitimate expectations do not include expectations based on self-interest at the expense of the public. Examples of legitimate expectations include the provision of emergency services and services with high public health values such as immunization, preventive and promotive services, and the treatment of infectious diseases.
One measure of the response to the legitimate expectations of individuals is satisfaction with services. Satisfaction has multiple dimensions including access, cost, and quality of care. There is a significant difference in the satisfaction with health systems between countries. Satisfaction with health services in the community can also be compared within regions in countries and between the public and private sectors.
Improving the efficiency of health system
The efficiency of a health system depends on the allocation of resources to services with high public health values (allocative efficiency) and the provision of technically efficient services (technical efficiency) including clinical services. Technical efficiency involves the use of cost-effective services and some form of competition and market mechanism, and therefore can apply readily to the private sector. Measures to improve the efficiency of a health system may be in conflict with measures to reduce inequities. Nevertheless, measures to reduce inequities using public resources must also be efficient. This gives rise to the notions of hierarchy of objectives in community diagnosis. It is difficult to prescribe the optimal mix between equity, efficiency, and satisfaction with services. The challenges are to use the available resources to best achieve health system goals agreed upon by the society.
There are variations in health-care expenditures with respect to the gross domestic product of countries. Thailand spends more on health as a percentage of gross domestic product than Malaysia but has a lower life expectancy and higher infant mortality than Malaysia. Theoretically, the private sector can enhance the efficiency of health care through the provision of good services at a competitive price. However, it is not known whether the changing proportion of the private sector correlates with efficiency (Newbrander 1997) because the public sectors of countries have monitored the pricing and quality of private services with differing levels of rigour. Some information for planning health care has to involve centralized efforts to monitor service standards and to protect the public. Information is needed to monitor financing, provide services at public and private facilities, and to enable the public to make appropriate choices.
Protecting individuals and enhancing fairness
Protecting individuals and enhancing fairness are two important goals of health. Citizens of a country have a right to a certain level of health regardless of whether they are rich or poor. Rights to health promotion services, disease prevention such as immunization, treatment of emergencies, and acute infections are some examples. Governments can involve the stakeholders to determine the level of health all citizens will have within the constraints of limited resources.
Each of the objectives can serve to indicate directions for the development of variables to measure the current health situation as well as to assess changes with time. A good variable has to be reliable, valid, sensitive to change, and credible to the stakeholders.
Although fulfilment of many of these objectives would lead to similar decisions, this may not be true for all cases. For example, coping with inequity by focusing on the health of the underprivileged groups to enhance social justice will require different decisions than improving the average health status of both the élites and the underprivileged groups of the society.
Without clear objectives of the health system, the demand for good information missing in the information system can be used as an excuse not to plan a programme. One important argument for not using information for planning is that information is not accurate and basing a decision on incomplete information can do more harm than good. Therefore, a clear objective will identify the minimum information needed to make decisions. A clear objective will help focus on the improvement of an information system to enhance its utility to meet the objective. A balance can then be struck to see whether a minimum level of useful information exists for the decision. In the case of inadequate information, efforts to collect additional information through a rapid survey or focus group discussions can fill an information gap in planning.
Components of information systems for planning health care
The major components of health care which will need systematic information for planning include information about (a) health situations and needs, (b) the availability of resources to deal with those needs including the various approaches to organizing and financing of the resources, (c) the organization and capacity to take those resources and convert them into services (that is, the performance of the system: efficacy, effectiveness, efficiency, quality, and decision analysis), (d) variation of use, and practice with their implication on equity to access and coverage, (e) the impact on health outcome, and (f) the consequences of health-care financing on politics, the economy, and society as well as on the welfare of the entire population.
The users and contributors of information for health planning can be policy analysts, health-care providers, epidemiologists, social scientists, and economists, among others. The gatherers and users of health information are often different people at different levels of the health-care system. For policy decisions, policy analysts will need information to facilitate policy recommendations. Those who provide health services and have the task of being accountable for the services they provide should also be involved in the development of an information system. The general areas outlined above differ among developed and developing countries, not with respect to the problems themselves but rather to the emphasis given to each of them.
The measurement of needs
With respect to the measurement of needs, it is important to understand current needs, trends, and types of services needed (promotive, preventive, curative, and rehabilitative), including both objective and subjective needs. The differentiation between need, demand, and utilization is also crucial (Box 1).
Box 1 Health care need

Current needs:
real need versus want
effective demand
use
prioritization

Trends, for example in AIDS and related conditions, ageing, trade

Types: promotive, preventive, treatment, rehabilitation

Validity and objectives of data sources

Real needs are those that require appropriate fulfilment and they may be both felt or unfelt. Demand is generated by felt need, and needs and demands require effective provisions. Effective provisions represent the capacity of the health systems to satisfy the real needs within the technological and other resources of the society. Use is not the same as effective provision although it is easier to measure. This is fundamental to the author’s approach to the problem. Utilization reflects the perception of health need, individual reaction to symptoms of ill health, resources that the individual must invest to acquire the service, ability of the facilities to provide the service, and benefits that the providers of service expect to generate. It does not tell us what volume of service is optimal. It is important to know what volume of health services should be consumed, not just how they are actually consumed, to decide upon the likely benefit of a particular investment. Without appropriate data, decision-makers might focus on ineffective provisions without meeting needs. A needs-based system is difficult to establish but is essential to allow people to be more responsible for what they do in terms of their own health.
Current needs only represent part of the picture in planning of health services. The health system has to be more aggressively involved in the trends of diseases such as HIV infection and AIDS, with the emphasis on finding more effective means of delivering educational and other preventive programmes which highlight high-risk activities. With the new industrialized trends of developing countries, occupational diseases will be increasingly important. The current trend of population demographics may require a greater emphasis on the needs of the elderly who may claim a greater share of the funds provided by the various health-care schemes.
In the analysis of the types of effective provision, it is necessary to understand the need to establish a balance between preventive and promotive strategies versus treatment and rehabilitation.
It is important to develop an information system in both developed and developing countries to measure incidence and prevalence of objective and subjective needs as well as the use of specific types of health services to fulfil those needs.
Fulfilment of non-health needs can also lead to health improvement. For example, the role of women in determining the health and life prospects of their children is crucial. It is therefore important to find ways to assure women’s health through nutrition, education, gender equality, and health practices. How can social and other non-health interventions interrupt the vicious circle of poverty, health, and the lack of social development? This area will remain important for future research.
Information about the organization and financing of a health service
The organizational arrangements for health-care financing and delivery are also important components of an information system to ensure universal coverage and equity of access.
The organization
Ideally, the structure that should be involved in a health service system are the public health facilities, the private sector, other communities, the workplace, and families and individuals. Major activity is currently occurring in the public sector, particularly the ministries of public health. Information about other components of a health system must also be sought. So-called ‘unqualified’ personnel or ‘minimally trained community-based health-care workers’ for workplace communities, family support, and self-care, can be trained to become resources for health-care currently provided by higher level professionals (Box 2).
Appropriate personnel requirement is also an important issue. It is important to identify the appropriate proportion, type, qualifications, and distribution of personnel required to support the health-care financing schemes. How much should currently ‘unqualified’ personnel be trained to support the system? What is the role of informal care and self-care?
Privatization will not facilitate universal access to health care. It will, however, affect the financing and payment system. More active work and more cross-cultural comparisons are needed in this respect, particularly where more privatization is developing in many countries, including those in Eastern Europe. Information will be needed to monitor the extent to which these trends can alter the basic relationship between patients and health-care professionals resulting in an impact on health and the quality of services as well as on the livelihood of people.
Box 2 The structure and the organization of a health system

Structures
public: ministries of public health, local government offices
private sector
workplace
home

Personnel requirement
specialist/generalists
nurses
currently ‘unqualified’
informal care
self-care

Population being served
based on workplace
based on residence
other

Co-ordination

Finally, although some resources are needed for mounting and co-ordinating an information system, it is important that the proportion of resources allocated to co-ordination not be so substantial as to jeopardize other activities. However, the information base to do such analyses may not exist and therefore may need to be constructed.
Information on financing
The framework for analysis of the financing of health services is depicted in Box 3.
The factors affecting the various sources of health-care financing mechanisms vary between countries. In this complex situation, it is important to resolve questions over who pays, who receives payment, what is being paid for, who eventually benefits, and how to ensure sharing and pooling of the risk of ill health to attain a certain degree of equity.
Box 3 Financing of health systems

Who pays?
insurance scheme
employers
government (welfare)

Pay for how much?
total
percentage of gross national product
trends

Pay for what?
types of services
levels of services
specific activities

Pay to whom?

Basis of payment
fees for services
capitation
co-payment

In order to monitor and determine the appropriate emphasis of the programme, the total amount of payment under the various health-care financing schemes, its trends, the relative proportions of the various schemes, and the percentage of gross national product used for each scheme need to be assessed.
The relative contribution of the various health-care financing schemes for preventive, promotive, curative, and rehabilitative care is also important to guide the setting and monitoring of the appropriate proportion of these various services. Related to these issues is the relative contribution of health-care financing schemes to the various levels of services: primary health care, primary medical care, secondary medical care, and tertiary medical care.
The basis for payment under the health-care financing schemes will be important for determining the rate and the appropriateness of utilization of services.
The alternative models
Each of the alternative models has their strengths and weaknesses. Each of them may be considered appropriate for meeting the needs of health services, depending on the situation. However, there are some common targets of all models of financing. These are equity, efficiency, stability, sustainability, administrative feasibility, health impact, as well as impacts on the socio-economic and political systems of a society. As there are numerous ways of organizing resources, alternative models have to be developed, tested, and compared.
Resource allocation and utilization of services
In allocating resources, it is important to define practice variations and use variations (including issues of acquisition, diffusion, use, and control of access to health technology). Practice variations result from the decisions of roviders while use variations are the consequences of consumer behaviour (Box 4).
Variations of service provision can depend on which scheme is used to pay health-care providers (for example, fee-for-service scheme or capitation). The rate of certain procedures might be inappropriately increased if the fee-for-service scheme is adapted to the point that the financing system cannot be sustained because of a greater emphasis on treatment than prevention. In Australia, for example, the rates of obstetric intervention in private patients have been higher than for non-private patients (Roberts et al. 2000). The views of specialists differ on whether or not to perform cancer genetic testing and carry out prophylactic hysterectomies when patients prove positive (Matloff et al. 2000). If coverage refers to the degree to which effective provision is given to those who have real need, it is not always true that more services lead to more coverage. Conversely, hospitals may avoid providing standard services if they are costly, or may not join the health-care financing schemes programme if a capitation scheme is in place. If the hospitals fail to provide high-cost but already proven efficacious and standard care because the services are too expensive, certain ethical issues may arise. A good information system should be able to identify these issues.
Box 4 Resource allocation and use

Practice variations among providers
special ‘track’
over or under prescription of technologies
provider satisfaction

Variations among users
underuse
overuse
user satisfaction

Access, equity, coverage
among social insurance clients
among clients of other insurance schemes

Allocative efficiency

On the one hand, people who are covered by private health-care financing schemes might overutilize health resources because they perceive that it is their right to obtain services. On the other hand, people might underutilize services under certain health-care financing schemes because they may perceive that they are receiving inferior care.
Services that are overutilized might lead to inequitable access to services of other low-income groups. If coverage refers to the degree to which effective provisions are given to those who have real needs for services, it is not always true that more services lead to more coverage.
An information system has to associate appropriate population denominators with the numerators, particularly where the people in a catchment area can use many different financing schemes for the same health condition. In this general area, the topics of national relevance are those of access, equity, and coverage as they relate to factors including income, age, sex, and occupation.
Health system performance
Measures of health system performance are becoming increasingly important as the financial demands of health care have put increasing pressures on national economies (Box 5). Although some of the most exciting work is taking place in developed countries, much is happening in developing countries as well. The field of epidemiology has made a great contribution to public health and health-care research. Epidemiology, political mapping, decision analysis, health system economics, and evidence-based practice have helped revolutionize the practices of medicine and public health. Epidemiology, however, supplements but does not replace basic sciences. The major problem for measuring health system performance is the availability of data. Information systems therefore need to be strengthened to be able to track the performance of public health interventions.
Box 5 Health system performance

Efficacy

Effectiveness

Operative efficiency

Clinical decision analysis

Outcome and epidemiology of medical care

It is not only the expensive technology of public health and clinical medicine that is subjected to the analysis of health system performance, but the very inexpensive and moderately priced everyday practices also need to be evaluated. Information systems are needed to track preventive activity such as immunization programmes, screening for chronic diseases, availability of early treatments, and risk factor counselling.
Decision-makers and health providers must have the skill to evaluate their own decisions and practices, and to be more accountable in their decisions. The design of a good information system should empower these practitioners to ask questions about public health interventions. Such an empowerment should lead not only to heightened expectation and demand for quality and accessibility at reasonable cost, but also create an environment in which the information system for public health decisions has reason to grow. A more systematic approach to information systems is needed. Information and technology gaps between developed and developing countries in this area need to be narrowed. Only then can the strategies to define an optimal health care for all be achieved.
It is important to make providers accountable for their services. This requires information support. Information should not be an exercise that can only be performed in university faculties. The task of the specialists in information systems is to make the methods as accessible as possible. The emphasis in much of information system research in the decade ahead will shift from a traditional study of inputs (for example, personnel, facilities, procedures, appliances, drugs, and so on) to the evaluation of health-care output and performances.
Information on health outcomes
Outcomes of care are usually measured using mortality and morbidity rates. While these are important indicators, they do not take into account the impact of illnesses and death on the individuals and their families as well as on the economic and social well being of the society. The death of a child in a family might have very different consequences from the death of the mother; in many societies, such as those in Africa, the death of a mother might lead to the death of other children and disintegration of the whole family. Deaths of young adults have more impact on the production of the society than deaths of the incapacitated elderly. Therefore the definition of outcome of care needs to take into consideration the lifetime consequences of illnesses, impact of illnesses and death on other family members, the well being of society, and productivity (Box 6).
Box 6 Health outcomes

Definition
functional status
well being

Health status measures
single index from aggregates
utilities
preferences

Defining outcomes of care
An exciting feature of health-care analysis is the ability to access information to measure outcome, for example measures of functional health status and well being. This field has previously not received enough attention. More people are doing research on what it means to have certain physical limitations. Functional health status is complex and the study of it can provide important information. More research on quantitative measures of well being, including the quality-adjusted life year, is needed. It is hoped that methods will be developed to measure these not only in individuals but also in communities.
Health status measurement
Far more attention needs to be spent than previously on health status measurements including (a) the aggregation of various health indicators into single indices, (b) deriving the utilities and preferences for various health states, (c) the measure of possible health states across the various health conditions, (d) the measure of health status in children and the elderly (most of the current measures of health status apply to adults), and (e) evaluation of clinical treatments and changes in health-care delivery.
Information of development policies affecting health
A public health system is very different from a health-care system. The public health system needs to provide information on development policies that can affect health. These include policies on the macroeconomy, agriculture, energy, and housing (Box 7).
Box 7 Development policies affecting health

Macroeconomic

Agriculture

Industrial

Energy

Housing

Planning a public health system requires information on the ecology and environment, schools, workforce, social care, housing, and alternative energy sources in addition to information about the performance and integration of various levels of health care as described above. Public expenditures and subsidies to stimulate macroeconomic growth may be done at the expense of support for essential drugs, employment programmes for the poor, and so on. Agricultural development can exploit land use, which can change biodiversity and thereby promote emerging diseases and resistant strains of micro-organisms. Agricultural development can also affect the short- and long-term health of migrants and local people through the use of pesticides and acute poisoning. Improvement in irrigation systems can change the lifecycle of vectors and complicate water-borne diseases. An information system to monitor work safety and pollution should go along with the development of industrial policy. To promote safe energy, information is needed on the sources of energy (for example, the effect of hydropower on deforestation and health), consumption of energy for cooking, household use, transport, and pollution standards by industries, and pricing policy related to the use of safe energy. Information on housing policy can cover issues such as health problems in slums and government housing, safety of high rise buildings, availability of public services, cost of rent compared to cost of food, and hygiene standards.
The general framework for community diagnosis
Defining the community
The first task to define health and disease burden in a given community is to define the target community. This can be a country, province, district, or state, but might be a more defined geographical region, such as an urban inner city, or a socially defined group, such as poor communities, women in the reproductive age range, pregnant mothers, infants, young adults, or the elderly. The target population should be broad enough to cover all subgroups relevant for the assessment of health situations outlined by the objectives such as equity of access to care. If the target population is not well defined at the outset, there could be a tendency for the subgroups from whom data are easily obtained to be over-represented. For example, disease patterns from hospital data under-represent those who have limited access to hospitals.
Health indicators
The definition of indicators is a pre-requisite for the development of an effective information system in community diagnosis. Indicators have to reflect the kind of decisions which will be needed to estimate the burden of illness and the strategies for control.
Positive and negative health
Ideally, health indicators should reflect both the positive and negative aspects of health status. The new definition of health by the WHO includes the physical, mental, social, and spiritual aspects of health. Many attempts have been made to develop measures of quality of life as a proxy of positive health (e.g. the WHO quality of life instrument (Anonymous 1995)). Positive health measures have not been widely used in developing countries partly due to cultural influence on the expectations of people. Poor people in developing countries are more likely to accept the limitation and be satisfied with poorer health than their counterparts in wealthier countries.
Good health tends to be unnoticed until obvious symptoms from diseases have occurred. The concept of the ‘burden of risk’ can be brought to the attention of public health officers if there is a method to modify the course of presymptomatic illness. Thus screening for hypertension is an essential public health tool because of the possibility of modifying the course of hypertension and preventing stroke. Screening for diseases can be a part of community diagnosis if a cost-effective intervention is available for modifying the course of the disease once identified at screening.
In most developing countries, health information systems are principally oriented towards negative aspects of health because of the relative ease of their measurement. People will seek help from the health-care system when they become ill. The main health indicators are expressed in terms of crude age-adjusted or age-specific mortality rates (such as infant mortality rates, mortality for children under 5, or maternal mortality rates), disease-specific morbidity rates, and life expectancy at birth. Mainly because diseases have different natural histories and impacts, other indicators have been developed. Examples include potential years of life lost, quality-adjusted life years gained, disability-adjusted life years, healthy life years lost, and disabilities and quality of life index (Murray and Lopez 1996; Hyder and Morrow 1998). Debate has continued over the assumptions that these measures make, such as the relative values of time lived at different ages and the application of discounting rates over time. Many maintain that the implications of age weighting and discounting are unacceptable. Those who disagree with allotting relative values to time find it difficult to trade healthy years by giving less weight to future generations in favour of the present generation. Those who agree with age weighting and discounting feel that such methods of weighting and discounting are consistent with the necessary allocation of resources, for reasons of cost-effectiveness, and with avoidance of giving less value to childhood death. In view of this debate, it is important for developing countries to focus on the development of information that can measure mortality and morbidity rates with some degree of certainty. These standard indicators can later be transformed to calculate other newer indicators after agreement has been reached over the various methods.
Sources of information and the methods that can be used for community diagnosis
Information for community diagnosis can come from many sources (Box 8). Examples include routine reporting from health facilities, surveillance, screening, special surveys, contact tracing, vital registration, and a combination of several methods including using qualitative information to define variables and continued surveys of the nature and extent of the problems once the variables are defined.
The details of these approaches are addressed in the next section.
Box 8 Sources of information and methods for community diagnosis

Routine reporting from health facilities

Surveillance including active, passive, and sentinel surveillance

Screening

Special surveys

Rapid surveys

Contact tracing

Vital registration

A combination of several methods

Trend analysis
Information can be gathered and analysed for changes over time. Trends in the health status of a nation and a community involve demographic transition, urbanization, education expansion, changing status of women, economic transformation, politics, technological innovation, and global integration including the international transfer of risk (for example, pollution and global epidemics), trade liberalization, and shared learning leading to accelerated development and interdependencies. Assessing trends can be done in terms of health situations, burden of illnesses, and risk behaviours (Ungchusak et al. 1996; Kitsiripornchai et al. 1998; Mills et al. 1998), and can be used to assess the effectiveness of an intervention (Muller et al. 1995).
Characteristics of community diagnosis
The basis of community diagnosis is to learn whether the community has achieved the objectives proposed by the policy and programmes in use. There are several desirable characteristics for community diagnosis:

ability to address important problems amenable to practical control

ability to identify most of the target health events

adequacy in reflecting changes in distribution of events over time, place, and person

having a clearly defined population, data collection, data flow, analysis, interpretation, and feedback

orientation towards appropriate action

being participatory, uncomplicated, sensitive, timely, and inexpensive.
Sources of information and methods for community diagnosis
Routine reporting system
In developing countries, death registrations are incomplete and disease notification is unreliable. The information most readily available is from health facilities such as clinics and hospitals. The number or proportions of patients who seek care are commonly presented to indicate the burden of illness. This method has particular appeal because of its simplicity and low cost. Routine reporting from hospitals and health facilities can give useful information on the health status and burden of illness of a target catchment area to plan and monitor health services if survey information is not available or gives incomplete information. For example, the burden of illnesses and priority ranking of disease in Ghana has been based mainly on the routine information obtained from hospital facilities (Ghana Health Assessment Project Team 1981).
Information from routine reporting of the HIV seroprevalence among heroin users derived from different regions of a country can shed light on the rate of HIV infection at an early stage of infection (Table 1).

Table 1 Provinces with HIV seropositive drug users classified by region (Thanyarak Hospital: December 1987 to December 1988)

Information from the routine report of a key facility for the treatment of drug-dependent patients of Thanyarak Hospital (Thailand) indicated that the spread of HIV seroprevalence among drug users occurred first in the central region of Thailand including Bangkok, followed by the north, the south, and the northeast.
Routine reporting from health facilities has frequently been used to identify disease trends for health problems associated with stigmatization such as drug dependence and HIV/AIDS as shown in Fig. 1.

Fig. 1 Percentage of HIV-positive people among injecting drug users collected from routine reporting data from drug dependence treatment facilities at the Thanyarak Hospital, July 1989 to December 1997. (Data from V. Poshyachinda 1997, personal communication.)

When the information obtained from male addicts in one facility (that is, among new cases, revisited cases, and non-heroin addicts) was analysed, the seroprevalence among the new cases showed a declining trend (Fig. 2). Conversely, the seroprevalence rates among the old cases and the non-heroin addicts (not injecting) were stable. These trends suggested a possible change in the behaviour of the new cases of heroin injectors, which may have been due to a successful campaign by the authorities.

Fig. 2 Percentage of HIV-positive people among new injecting drug users, readmission cases of injecting drug users, and non-injecting drug users, at the Thanyarak Hospital, July 1989 to December 1997. (Data from V. Poshyachinda 1997, personal communication.)

Similarly, the routine reporting of the hill tribes people seeking treatment for drug dependence at the key Northern Drug Dependence Treatment Center (Thailand) showed a constant increase in the proportion of heroin users among this traditional people who used to smoke opium over the years as shown in Fig. 3. There was a rising trend of the percentage of injecting drug users among the hill tribespeople, indicating a shift in drug use pattern from opium smoking to heroin use first by smoking and later via injection. The higher percentage of injecting drug users compared with the percentage of heroin users since 1992 suggested that the hill tribespeople also injected other drugs.

Fig. 3 The percentage of heroin users and the percentage of injecting drug users among the hill tribespeople seeking care at the Northern Drug Dependence Treatment Centre (Thailand): 1986 to 1995. (Data from V. Poshyachinda 1997, personal communication.)

The increase in the percentage of heroin users seeking treatment has corresponded with an increase in HIV-positive prevalence among the hill tribe population up to 1994 as shown in Table 2. Despite the limitations discussed below, routine reporting can generate useful information for planning if analysed and interpreted with care.

Table 2 HIV seropositive prevalence among hill tribe heroin and opium users (Northern Drug Dependence Treatment Centre, 1992 to 1995)

Limitation of routine reporting: measuring utilization of services versus health needs
In developing countries, events reported depend on the use of facilities. This gives rise to a distorted picture of health problems in the community since many who need services do not have access to health facilities due to geographical, financial, cultural, and other barriers, or when the coverage of the population by such services is incomplete. It has been demonstrated that between one-third and two-thirds of diabetic and hypertensive people in a community either did not know that they had the diseases or did not seek hospital care (Wadswarth et al. 1971; Sitthi-Amorn et al. 1989). In addition, because the services provided by the various levels of health care are uncoordinated due to poor referral systems, one patient could seek care from several places and therefore be counted many times, leading to an overestimate of the burden of illnesses. Many factors can affect why patients use or do not use services including the reputation of health facilities, difficulty of access to facilities, and client perception of the seriousness of their illness. Thus, in using routine reporting, it must be remembered that the information available is not perfect and that the information needed may not be obtainable. A review of the information system must be done periodically to ensure that the information system provides the information desired for planners to meet the defined objectives of the health system.
Routine reporting is most useful in capturing most cases if a condition produces severe symptoms, and if the natural history of the condition is long enough to permit seeking treatment. Thus, a collation of routine hospital records can be used to produce cancer registries capturing most cancer cases in a community because most patients with cancer will have severe enough symptoms before death to seek treatment from health facilities. Conversely, a large proportion of myocardial infarction patients will die outside health facilities and therefore the records from health facilities alone will underestimate the true magnitude of the burden of illness from this condition. Likewise, reports from health facilities will underestimate cases of diarrhoea since many people only have mild symptoms and will not seek care.
The methods for detection of specific diseases between health facilities can create biased estimates in a routine reporting system. For example, differences in the incidence, prevalence, and mortality from coronary heart disease are observed between and within countries. In addition to the differing levels of risk factors between communities, these differences are also believed to be related to the different application of technology in health-care facilities. Medical care for acute myocardial infarction has changed significantly in the past decades, with the development of new methods for diagnosis and treatment. Although widely known, these technologies are not consistently applied for reasons of availability and cost, as well as local medical cultures and traditions (Luepker and Herlitz 1999).
To cope with the difference between utilization of major health facilities and the actual health need, an extended network of health facilities may be involved in community assessment of the nature and extent of a particular disease. Primary care doctors can play a major role in the identification of health problems, and the entry of patients into the health-care system. Patients with diseases such as acute low back pain usually recover within a short period of time, and in most cases major diagnostic studies are not required. The chances of these patients having significant pathology necessitating surgical or other forms of sophisticated intervention may be less than 1 per cent. Therefore, the patients may not seek treatment from major health centres. The involvement of primary health-care doctors can thus contribute to a better estimate of the burden of this illness (Rosomoff and Rosomoff 1999).
Outreach based on the samples defined in a health facility can also be used to determine the possible source of community infections. For example, in determining whether secondary cases of tuberculosis resulted from those dying in health facilities, a retrospective review of all cases of tuberculosis reported within a specified period was combined with a prospective evaluation of the molecular characteristics of new tuberculosis cases. The study revealed that cases of tuberculosis diagnosed after death did not appear to be significant sources of tuberculosis in the community (DeRiemer et al. 1999).
Efforts should be made to improve the quality of routine systems and to make use of innovative analyses of routine information because of the simplicity and potential usefulness of routine reporting systems (Kitayaporn et al. 1994, 1996a,b; Mastro and Kitayaporn 1998). Unfortunately, in many countries, significant progress in this direction is not expected. Therefore it is important to supplement routine reporting systems with other methods of estimating the burden of illnesses including screening, surveillance, special surveys, rapid surveys, and contact tracing.
Surveillance
Surveillance is considered a tool for community diagnosis of diseases which have the potential to become an epidemic, thus affecting many people in the community or internationally. Surveillance has been traditionally applied to the control of infectious diseases. The new paradigms of public health require that surveillance include the detection of toxins, hazardous chemicals, and genetically modified products. Of particular importance are the diseases transmitted from animals to humans, such as the outbreak of chicken influenza virus in Hong Kong and nipah virus in Malaysia. The influenza strains transmitted from birds to humans can cause widespread infection. Thus, surveillance has to be supplemented with strategies to detect the transmission of species-specific infections, which occur between humans and animals.
Depending on the nature of the diseases, surveillance can be active, passive, or targeted periodically towards special groups seeking treatment from sentinel sites. To be effective, a surveillance system must be integrated with other measures to take control of the spread of diseases under surveillance. The role of surveillance is:

to monitor secular and long-term trends of diseases and public health issues

to provide early warning for disease outbreaks

to evaluate prevention and control programmes

to monitor the effect of climate changes.
Effective surveillance of infectious disease has to be international in scope to monitor and share information on such diseases as Ebola, dengue, and plague.
Three types of surveillance can be used to diagnose the nature and extent of a health problem in a community: active surveillance, passive surveillance, and sentinel surveillance. Each of these types has its own sensitivity of detection of a health problem and has different requirements. Most countries have only passive surveillance systems because maintaining an active system is very costly and often requires some sophisticated laboratory support. Considerable infrastructure and human resources are required to maintain a sentinel surveillance system.
Traditionally, the main use of surveillance systems has been to monitor epidemics of infectious diseases. Recently, surveillance has been increasingly used to detect toxins, such as pesticides in human milk and lead in the blood of children, as well as deficiencies of trace elements such as vitamin A, zinc, folic acid, and iodine in adults.
The world has recently seen increases in diseases and epidemics in others that were once controlled. Since the middle of the twentieth century, antibiotics combined with improved sanitation, housing, nutrition, and vaccines have led to a dramatic drop in many infectious diseases that once killed millions (WHO 2000b). By the early 1960s, infectious diseases began to be controlled and these campaigns were so successful that many predicted their potential eradication. This created complacency among public health officials, policy-makers, and the public, which led to many policy and technical problems such as a decline in political and economic support for infectious disease programmes. This has led to the development of drug-resistant microbes, resistant vector strains, and the re-emergence of diseases once under control. There has been a decay of infrastructures and a shortage of trained personnel to deal with major infection control. One of the most important problems has resulted from the neglect of prevention in favour of using the ‘magic bullet’ or the ‘high-technology/quick-fix’ solution.
In addition to the relative neglect of comprehensive infectious disease control, other factors also contributed to the re-emergence of infection. These factors include an unprecedented world population growth since the Second World War, unplanned urbanization, uncontrolled deforestation, and agricultural practices such as reclaiming land which bring people closer to infective agents to which they have not previously been exposed. Changes in the pattern of biodiversity and environment may promote the transmission of emerging infections from animals to humans (zoonosis) such as Hong Kong chicken influenza virus and the recent outbreak of nipah virus in pigs. The emergence of new infectious diseases can also result from changes in irrigation systems, sexual practices, organic transplants (resulting in immunocompromised host), consumer goods (tin and plastic containers as breeding sites for mosquitoes), vehicles (tyres as breeding sites for mosquitoes and other vectors), commerce, and travel. These changes in practices and lifestyles are ideal mechanisms of constantly redistributing pathogens around the world.
Other factors include genetic changes in aetiological agents such as influenza (change in strains), development of antibiotic-resistant microbes and insecticide-resistant vectors, and an increase in vector-borne disease in general (through various hosts). These possible scenarios will need more research before scientists can fully understand the influence of genetic factors of micro-organisms on transmission potential.
Climate changes are imputed to help spread infectious disease but strong evidence to support this notion has yet to be found. The El Niño phenomenon has been imputed to have caused the spread of dengue in Indonesia and Thailand. Since dengue epidemics can be caused by many factors, the relative contribution of climate to the spread of diseases still needs to be clarified. Thus research is needed to see whether the degree of efforts to strengthen surveillance systems is needed in areas where more severe climate changes occur.
Surveillance can give information for policy-makers to act on which will help to reverse the trend of infectious diseases. Regulations and controls should be targeted at population growth, urbanization, and deforestation. Stronger emphasis must be placed on strengthening public health policy and public health rules that have been deregulated to give more rights to individuals but consequently, might harm the public at large. A better balance between individual rights and the good of the community must be established.
The public health infrastructure (including surveillance systems) in many countries, particularly in the developing world, must be improved, including personnel and laboratory facilities to deal with the major infectious diseases.
A key strategy is to rethink disease prevention from the public health standpoint, emphasizing disease prevention that includes such strategies as general hygiene, vaccines, vector control, public outreach, and education.
Surveillance systems for effective infectious disease prevention must provide information to promote:

effective emergency responses to outbreaks of disease

public and professional outreach to communicate important information effectively to key stakeholders such as the public, doctors, and government officials

effective community-based preventive strategies.
Active surveillance: a case study from India
Plague in India is a useful example to highlight the need for international co-operation and surveillance. In the first 25 years of the twentieth century, India lost about 12 million people to plague. The government launched an effective control programme, and in the 1950s plague was mostly brought under control. In 1959, plague had been eliminated from India, and in 1966, India was declared plague free. Subsequently, very little effort related to the control of plague was carried out. There was no laboratory doing diagnostic work for plague. In August 1994, an outbreak of pneumonic plague began in Maharashtra and moved into the city of Surat by September. The surveillance system did not pick it up. No one knew about it, not even the WHO. People started dying of pneumonic types of haemorrhagic diseases in Surat, an industrialized city of several million people. Some doctors consulted their old books and realized that it could be pneumonic plague. They sent samples to the laboratory for diagnosis, but the laboratory could not diagnose it. This created confusion, uncertainties, and a lack of confidence among medical communities. People panicked and 500 000 people fled the city of Surat. The WHO contacted the United States Centers for Disease Control (CDC) for assistance in identifying the microbes because it had the only functional plague diagnostic laboratory in the world. The CDC sent references and diagnostic kits to 15 countries in Southeast Asia and Europe. The WHO and the CDC were working blind and had to assume the worst. People from Surat fled to Madras, Bombay, and other cities worldwide, spreading the problem. There were reports about the spread in New Delhi and Pakistan, and the CDC worked with the WHO to intensify surveillance. Fortunately, rumours about the spread to other countries worldwide proved to be a false alarm and there were no cases identified from countries outside India. In retrospect, it was discovered that there was an outbreak of plague in Maharashtra and a few cases in Surat. There was no transmission to Bombay, New Delhi, Madras, and Calcutta. The lack of laboratory diagnosis capability had caused an epidemic of panic. There was a loss of 2 billion American dollars from the Indian economy and probably several billion dollars from the global economy. What should have been a focal public health event turned into a worldwide emergency. The WHO is not a policing organization and its actions are limited if countries do not want to co-operate.
The goals of active surveillance include:

to detect without delay the introduction of change in incidence of a specific disease agent: active surveillance has to be disease specific although there are some exceptions

to alert pubic health officials early about the epidemic—an early warning system (the emphasis is on the pre-epidemic period as opposed to the epidemic period)

to assess the extent of the risk of transmission of a particular disease

to estimate and monitor the effectiveness of control activities.
Active surveillance usually has to be laboratory based. The case definitions of an active system can vary. Case definitions can be non-specific in the pre-epidemic period but become more specific during the epidemic as the incidence increases. There must be standardized sample collection and reporting. The surveillance tool must be convenient and easily transportable (Frerichs et al. 1994; Cassol et al. 1996a,b).
When a clear disease definition is not available, syndromes can be used to cover multiple diseases. For example, although the basic diagnosis of dengue has to be laboratory based, a syndromic approach may also be used to increase case detection. The syndromic approach for dengue consists of three surveillance systems: clinic doctors, fever alert, and sentinel hospitals. When a syndromic approach is used, the case definition is very non-specific but should later be supplemented with more definite diagnostic techniques. In the case of dengue, the clinics and the hospital will be asked to submit to the laboratory information on a quarter of their viral syndromes every week. Fever alert allows blood to be taken for laboratory confirmation within 24 hours. Hospital deaths of all viral syndromes should similarly be laboratory confirmed and ideally autopsied (difficult in many countries). Individually, none of the three approaches is sensitive but collectively they become so. Clearly, the laboratory is critical to this type of effort.
The laboratory must be able to (a) conduct routine surveillance for priority diseases important in the area, (b) focus on epidemic transmissions of priority diseases, and (c) recognize new diseases, natural disasters, imported diseases, and bioterrorism.
At a minimum the laboratory should be able to conduct surveillance on priority diseases. If it is not capable of detecting the broad spectrum of new and other infections there must be some reference laboratory in the region such as a WHO reference laboratory where samples can be sent for identification and confirmation. Ideally, every country should have a national laboratory with satellite laboratories at the district and local levels. However, this can be beyond the means of poor countries. A more efficient way of sharing existing resources is to map out existing laboratory facilities in a region, co-ordinate sharing and standardization among them, and develop new facilities, which might be needed in the region. WHO reference laboratories should be capable of a wide array of diagnostic procedures. The WHO can also link up with other sophisticated laboratories such as the CDC in the United States.
Every national laboratory should have some well-trained personnel, enough facilities, equipment, and basic microbiology capacity. State-of-the-art technology such as the polymerase chain reaction assay is important but not as important as basic microbiology, which has frequently been ignored. The capacity to perform polymerase chain reactions at the expense of basic microbiology is a mistake because sophisticated equipment inappropriately used can create data that are misleading.
A mechanism should be in place to ensure quality assurance so that people have confidence in laboratory results.
Once an infection has been identified, the standard public health measures must be actively applied such as the identification of individuals, implementation of quarantine, implementation of sanitary regulations, the sacrifice of infectious sources such as animals, and measures to heighten precautions by individuals at risk. With acute emerging virus infections, there might not be time to develop vaccines and to find a treatment. In such cases, public health precautions will be the key coping measures. With bacterial infections, available antibiotics can be resorted to, some of which may be helpful.
Another example to highlight the importance of the laboratory is the concern for yellow fever. Yellow fever is a time bomb. An increase of yellow fever has occurred in Europe and the United States. This means that it can also be taken to Asia, and might remain there undetected because of insufficient laboratory capability. In the 1930s, there were major epidemics of yellow fever in Latin America. In 1947, the Pan American Health Organization implemented an Aëdes aegypti eradication programme to control the epidemics of yellow fever and dengue. By 1970, they had eradicated cases in much of Central and South America but they then abandoned the programme. Aëdes aegypti began to reinvade tropical America. There is the highest risk in 50 years for the occurrence of yellow fever in urban areas. If urban yellow fever begins to occur in Latin America with 300 million people, it will spread to other urban areas, particularly those with populations of over 1 million. This may also happen in Asia owing to ease of transport and travel. When this happens, the medical and public health communities might impute the illness to dengue, malaria, or leptospirosis. Therefore, the laboratory must be able to distinguish yellow fever from other diseases so health professional can react quickly and appropriately.
Passive surveillance
Passive surveillance is most useful for monitoring long-term secular trends but is relatively insensitive to tracking epidemics. Most countries have a passive surveillance system. The key components of a passive surveillance system include the use of standardized case definitions and a standardized reporting system.
Passive surveillance relies on doctors and health officials to report diseases and therefore is very insensitive for predicting epidemics. Constant communications, reference, and referral, together with political and economic support, are all crucial components of both active and passive surveillance systems.
Effective emergency response: a necessary complementary measure for surveillance An effective emergency response is an important element necessary for the effective prevention of the spread of infectious diseases. Good co-ordination between epidemiologist, laboratory personnel, and professionals in the field is critical. Effective control has to be disease specific. Knowledge about the dynamics of transmission is essential. Furthermore, there must be strong community involvement for sustainability and a real-time response and timely policy decisions. Even when a surveillance system has predictive capability, many policy-makers do not believe the surveillance data and, as a result, do not respond to the data quickly enough. Therefore, laboratory capability must be credible and understandable so that rapid decisions are made in real time rather than after the epidemic spreads or peaks.
Outreach: empowering the community to be integrated in surveillance diagnosis and control Outreach is an area where public health has failed. Despite the availability of health education materials by public health specialists for all kinds of diseases and health problems, people usually ignore them. Social scientists and medical anthropologists who know how to communicate with the community should be encouraged to play a greater role in developing health education messages. The use of the ‘scatter-gun’ approach, having one message for all recipients with diverse ethnosocial background, is unlikely to succeed. Education messages should be targeted at different groups, particularly the medical community (epidemiologists and doctors who must be well versed in diagnosis, treatment, and disease prevention), who use them to reach the public. The public must accept their own responsibility and not rely on the government to do everything. Government officials must make an honest assessment of what the epidemiologists have to say and must not have ‘selective hearing’, for example questioning epidemiological data to protect local tourism.
An integrated community-based approach must have common ownership and an emphasis on disease prevention. The approach must take advantage of all the updated technology and instruments available to cope with the epidemic and prevent disease. People must have a role in the programme and in setting the priorities of the programme. Government officials must not simply tell people how to do things. Without community ownership there is no sustainability. Policy decisions have to support a community-based approach.
Sentinel surveillance
A sentinel surveillance system can help to identify rapidly changing health problems in a country or community (Box 9).
Box 9 Selecting sentinel sites

Not necessarily representative sites

Likely to identify problems

High enough case load

Staff capacity and willingness

Data reliable

High-quality diagnostic capabilities

A good example is surveillance for HIV/AIDS to monitor the effectiveness of intervention programmes in Thailand.
In sentinel surveillance, the main objective is not to achieve representativeness of a health problem or an epidemic of the entire population. Rather, the objective is to track an approximate pattern or trend of the situation on which to base interventions. Sentinel surveillance allows monitoring of trends in specific groups within the community. Thus in Thailand, monitoring the year of first use of heroin can provide an estimate of when the next heroin epidemic may occur. Sentinel surveillance has been able to monitor the pattern of HIV infection among the people engaging in high-risk activity such as drug addicts, commercial sex workers, those infected with sexually transmitted diseases, expectant mothers, and military conscripts (Nopkesorn et al. 1998).
The results of sentinel surveillance must be interpreted with care. The critical factor is the issue of population change among different samples to estimate the magnitude of health problems. A prevalence of 40 per cent of HIV-positive people among drug addicts may give the impression that the situation of HIV spread has been stabilized. New cases of HIV-positive people among military recruits can give a better estimate of the trend in HIV-related problems in a country or community. However, the interpretation may be invalid if the rate of new infection equals the rate among the addicts who disappeared from the detection of the sentinel surveillance system either through migration or death.
Screening
The objective of a screening programme is to detect health problems at an early stage and link the problems with services which are effective in modifying the natural history of the diseases or to prevent cases with specific diseases such as HIV infection from spreading infection to non-infected contacts.
The target for screening can be the general public as well as those engaged in high-risk activity. Genital chlamydial infection is a common sexually transmitted infection that is often asymptomatic, but is associated with long-term morbidity in many women. Early infection can be diagnosed reliably using non-invasive methods and treated effectively with antibiotics. Screening for genital chlamydial infection in high-risk settings, such as genitourinary medicine and abortion clinics, has already been documented (Stephenson 1998). Screening in the wider community also needs to be evaluated since chlamydial infection is widely distributed among young sexually active people who may have little contact with health services. Studies are in progress to assess the acceptability of different screening approaches for both women and men in the community, and to compare the performance of newer diagnostic techniques. The cost-effectiveness of community-based screening for reducing morbidity needs to be evaluated empirically in randomized trials to encourage a coherent, evidence-based screening policy (Stephenson 1998).
Investments in national screening programmes should be based on benefits to the people who are found to be positive who can then be given intervention treatment or monitoring. Ideally, the evidence of such benefits should be strong such as evidence from a randomized control trial. In the United Kingdom, a national programme to screen newborn infants for phenylketonuria was introduced in 1969, followed in 1981 by a similar programme for congenital hypothyroidism. Decisions to start these national programmes were informed by evidence from observational studies. Subsequent national registers of diseases were used to measure the impact of the screening programmes. Differences and changes in infrastructure and standard instruments for screening within and between screening facilities over time can result in inconsistent policies and inequitable access to effective screening services, as well as to problems in the comparability of information. More recent developments in tandem mass spectrometry have made it technically possible to screen for several inborn errors of metabolism in a single analytical step. However, the availability of the instrument should not prompt decisions for screening. In fact, for each of these conditions, evidence is required that the benefits of screening outweigh the harm, ideally informed by evidence from randomized controlled trials. Setting a priority on what conditions should be formally evaluated can be an important challenge to the public health, clinical, and scientific communities (Dezateux 1998). Screening programmes have the potential to reduce the burden from mortality, morbidity, and disability, and to improve quality of life and livelihood, but they also have the potential to cause harm. A set of criteria will be needed to identify worthwhile screening programmes, develop strategies, and mount effective implementation that is agreed upon by stakeholders. A much more critical approach to screening is now being adopted. Efforts are being made to ensure that new programmes of proven benefits that are acceptable to the public, are effectively and equitably implemented in the community particularly if the resources from such a screening programme come from taxation. This issue will stimulate further discussion and debate among important stakeholders (Peckham and Dezateux 1998).
In developing an expensive screening programme, one criterion is to redefine the unacceptable by the stakeholders particularly the community. For example, the community might decide that it is unacceptable to have children infected with HIV. If so, couples will be encouraged to be screened and counselled for HIV infection if they decide to have a child. It is imperative to strengthen the community-based programme. Unless healthy populations and healthy communities decide to be involved, screening programmes will not be very effective. The communities must be encouraged to help providers and decision-makers help themselves.
Survey and special studies
The objective of a special survey is to gain insight into the nature and extent of a problem in a defined community. The problems to be surveyed may be suggested by information from routine reporting and the surveillance system. Surveys and special studies can answer a particular question relevant to a community when routine systems cannot yield adequate information for action. Members of the community can be involved in such a survey not only as collectors of data or joint explorers of local conditions but also as partners in interpreting the data and in determining systematically how to manage a problem. The community can also shed light on the cultural meaning attached to a disease or a condition (MacQueen et al. 1996; Van Landingham et al. 1997). An understanding of the survey results as seen from the standpoint of the people will enhance an understanding of the problem and improve the dissemination of the results of surveys to the community and thus empower the community groups. Primary health care workers can be the most important group to engage in the dissemination of information to the individuals. In the Philippines, health-care workers learn to identify the mosquitoes responsible for the spread of malaria and help conduct and read blood smears.
One example of a survey is to assess whether universal condom use to reduce the spread of HIV infection was effective as suggested by routine surveillance (Mastro and Limpakarnjanarat 1995). A survey was conducted and showed that a low rate of condom use occurred in lower social class commercial sex workers, construction workers, and poor truck drivers. The seroconversion rates of HIV among these sex workers was shown to be on the rise (Sawanpanyalert et al. 1994; Mastro and Limpakarnjanarat 1995; Kilmarx et al. 1998). Many commercial sex workers did not use condoms if they were entertaining ‘regular customers’, if they drank, or if they believed that healthy people had no risk of HIV transmission (Vanichseni et al. 1993). The special survey was an important supplement to the information gathered from routine surveillance for designing effective control strategies.
A special survey was also conducted among housewives in Thailand to clarify the reasons for a rise in HIV infection in pregnant women. The survey showed that there was a significant difference in attitude between the Thai housewives who were HIV positive and those who were HIV negative. Those who were HIV positive were not confident at discussing HIV disease with their partners. They were also less likely to tell their partners first if they were infected (Suwanagool et al. 1995). Special surveys also helped to clarify the risk of perinatal transmission (Shaffer et al. 1999), and the rate of discordance of HIV status between pregnant women and their partners (Siriwasin et al. 1998). This special study helped to design a public health campaign aimed at addressing the increase in HIV prevalence among pregnant women discovered from the sentinel surveillance system.
Training of interviewers and enumerators for valid data collection is required for epidemiology studies. Qualitative data to identify variables meaningful to a community, reflecting their voices, and bringing in the human dimension of a problem can be a powerful complement to epidemiological surveys which highlight differences between groups. Therefore, public health surveys and special studies have embraced methods from the social sciences in the identification of variables for surveys as well as the interpretation, dissemination, and use of results.
Large-scale health surveys conducted by government agencies, which record information on a large number of health-related variables, are available for analysis. The information can be applied to estimate demographic profiles associated with possible lifestyles and biochemical determinants of diseases. It can also estimate the probability of receiving some clinical services and screening according to the type of health insurance, the probability of receiving a digital rectal examination, and the effectiveness of community intervention to encourage positive lifestyles such as smoking cessation (Graubard and Korn 1999). Special studies which follow cohorts can detect changes in epidemics and behavioural factors (Limpakarnjanarat et al. 1999).
Rapid surveys
The objective of a rapid survey is to collect information required to make decisions to cope with urgent health problems when the true nature and extent of the problem is unknown. Large surveys are usually expensive and cannot be done frequently or timely enough to assess or evaluate health problems in a specific area. Furthermore, it is unwise to infer the results of a large general population survey for local planning (Smith 1989). A rapid survey can be used to collect population-specific information on health situations, on possible determinants of disease, and on knowledge, perceptions, and cultural aspects of illnesses. A typical rapid survey can be carried out by sampling 30 clusters of seven to ten respondents (or households), each covering 200 to 300 household interviews (Henderson and Sunaresan 1982; Frerichs and Tar Tar 1989). These methods have been used to assess the status of immunization, family planning, and use of antenatal services.
Contact tracing
Contact tracing is particularly useful when information from routine systems and surveillance suggests the need for a clarification of the pattern of the spread of diseases (Box 10). It is also useful to estimate acute illness episodes and disease problems among illegal migrants and mobile ill-defined populations such as tourists and migrant workers. The purposes of contract tracing (community visiting team) are to confirm the diagnosis, determine the extent of secondary transmissions, and estimate the pattern of risk behaviours.
Box 10 Purpose of contact tracing

Confirm diagnosis and find causes

Behaviour risk estimates

Estimate magnitude of problems

Identify possible control measures

Identify where/to whom to apply control measures

Recommend control measures

Contact tracing can lead to more cases contacting the patients who failed to come to receive service from the health-care system and thus increases the validity of the estimates of the magnitude of problems. In addition, better targeting of control measures can be a desirable outcome, leading to increased efficiency of the health system.
Contact tracing was carried out for heroin users seeking treatment from Samutprakarn Hospital in Thailand (Table 3) to identify the magnitude of needle-sharing behaviours among the confirmed addicts.

Table 3 Drug use and travel pattern of 731 injecting heroin users treated at Samutprakarn Hospital

Through contact tracing, drug use and needle sharing were identified as a mode of spread of HIV infection from the urban to rural areas. The result gave rise to the design of a prevention programme aimed at reducing needle sharing among addicts during travel. Contact tracing could also document the spread of HIV infection among convicts through needle sharing in prisons.
International travel can be one of the major modes of transmission of HIV. Estimates of contacts of tourists with sex workers, beach boys, and massage parlour attendants through surveys and contact tracing can help clarify the magnitude and pattern of disease transmission (Mulhall et al. 1993). Migration also occurs across borders for jobs in construction, factories, logging, and commercial sex work (Asian Research Center for Migration 1999).
Vital registration and census
Vital registration relies on the requirement by law to report health events including birth and death. These figures can be obtained from the national statistical offices and relevant departments such as health, welfare, education, and the ministry of interior. Many countries also have periodic censuses every 10 years.
There are examples in developing countries where events are under-reported due to the lack of quality assurance of the reporting system, even to document all deaths. For example, the accuracy of perinatal and infant mortality rates in most developing countries is questionable. The perinatal and infant mortality rates in a rural district of Thailand as measured from surveys were compared with the official statistics to assess accuracy. All stillbirths and 45 per cent of infant deaths were unregistered (Lumbiganon et al. 1990).
In addition, the inaccurate enumeration of deaths and inadequate medical certification of deaths in developing countries limits the ability to infer the cause of death, particularly in those occurring outside hospital or clinical settings. In Thailand, the causes of mortality were defined only in about 40 per cent of all deaths. Verbal autopsy and lay reporting have been used as methods for estimating the causes of death (Snow and Marsh 1992; Kleinman 1978) through data gathered from relatives and friends. Verbal autopsy has been widely used for the diagnosis of causes of child mortality. Standard criteria have been developed for the diagnosis of common causes of childhood mortality to allow a comparison of the results of different studies (Bang and Bang 1992). Such standard criteria will be needed to acquire data on cause-specific mortality for evaluating disease prevalence and for targeting, monitoring, and measuring the impact of interventions.
A combination of several methods: an example
All academic disciplines for community diagnosis have both strengths and weaknesses. To solve a public health problem adequately requires inputs from several disciplines and approaches either through composing multidisciplinary teams or training public health researchers to move beyond disciplinary boundaries.
A combination of several methods has been used to understand the epidemics of HIV infection in Thailand. An epidemic among drug users was predicted by routine reporting from various drug dependency treatment centres (Ministry of Public Health 1997). In addition, routine information from drug dependency treatment facilities also suggested the spread of the epidemic from Bangkok to the provinces and from the urban to rural areas. Different incidence rates occurred in various geographical areas at any point in time. The HIV epidemic in specific regional areas, such as the hill tribes drug user population discussed above, most likely occurred at different times from 1987 to at least 1995 if not after (Beyrer et al. 1997). HIV infection in non-injecting drug users consistently persisted due to sexual behaviour. Contact tracing showed that travelling, needle sharing, and imprisonment interfere with intervention efforts to stop the spread of HIV infection. Periodic special surveys showed that a reduction of risk behaviours such as needle sharing could be achieved in a relatively short time with timely implementation of appropriate interventions. They also documented the epidemiological evolution of HIV-1 subtypes B and E among heterosexuals and injecting drug users in Thailand (Limpakarnjanarat et al. 1998; Poshyachinda 1993a,b). Moreover, routine reporting and sentinel surveillance supported the notion that the prevalence among injecting drug users in the rural population and minority groups was still low when preventive interventions were introduced. Nonetheless, the prevalence in these populations increased to the level of Bangkok and the central region.
Sentinel surveillance has demonstrated the development of infective pools of HIV infection among intravenous drug users and commercial sex workers in Thailand. Special surveys and contact tracing among the clients of sexually transmitted disease clinics and among the migrant workers helped clarify the transmission among the high-risk and socially deprived groups. Also, through the sentinel surveillance of pregnant women visiting antenatal clinics, military conscripts, blood donors, and outpatient clinics, the epidemic was shown to have spread from the infective pool and high-risk populations to the general population, and subsequently demonstrated the reduction of the rate of the epidemic through effective control (Fig. 4). The story of an information system and various methods for community diagnosis of HIV infection has emphasized the need for a combination of approaches to understand the evolution of a public health problems as well as the effectiveness of control measures. It also showed the value of various types of information system in explaining aspects of epidemics leading to effective control.

Fig. 4 Model of transmission of HIV infection in Thailand derived from various methods of community diagnosis. IVDU, intravenous drug user; STD sexually transmitted disease; CSW, commercial sex worker; ANC, antenatal clinics; OPC, outpatient clinics.

Finally, the information system and attempt at community diagnosis will only be possible if done in concert with political commitment and effective administration and planning which balances the evidence and values collected from different stakeholders within the society (Phoolcharoen et al. 1998a,b).
Technological limitations of information systems and community diagnosis
Even if the data for community diagnosis are valid, methodological advances are still needed to help set priorities for health needs.
Estimates of lifetime effects on individuals with particular health problems
Many health measures such as person years of life lost, healthy days of life lost, disability-adjusted life years, and quality-adjusted life years attempt to introduce time dimensions to the evaluation of health and diseases. These measures are not likely to correspond to social preferences and social investment in the individuals before death occurs. The social preferences probably vary between cultures and therefore an attempt to make global estimates using common measures might not be valid to compare burden of illness. Particular care must be used if these measures affect the allocation of resources across countries.
Effects of health problems of individuals on their relatives
The loss of the main source of income through death is not equivalent to the death of a dependent in a family. Therefore, deaths will not be equal among members of a household depending on many factors. These include the changes in social status caused by widowhood or orphanhood, changes in the dependency ratios of the household, and the reallocation of work responsibilities between household members. Other significant factors are the reallocation of domestic responsibilities, changes in major sources and the levels of income of the household in which deaths occur, changes in ownership and indebtedness, and expenditure due to medical bills or funeral costs.
Therefore, the community needs to be consulted to see whether the community diagnoses accurately reflect their perceptions of the values given to deaths and illnesses, particularly when decisions on the allocation of limited resources will be based on such a diagnosis.
Universities have a definite role in helping to overcome the technological limitations of information as well as to guide and direct the society with respect to appropriate community diagnosis and appropriate control measures. Academics should meet the challenge and accept responsibility not only by teaching and in-depth research but also by advocating the most appropriate methods for community diagnosis in the light of limited resources.
Information systems of developed and developing countries
In developed and developing countries, mortality reporting, registrations of some diseases (such as cancer), routine reporting, and census data have been the main sources of information used to estimate the burden of health problems. These generally have been supplemented by household surveys and periodic population-based survey such as the National Health Examination Survey, the National Health and Nutrition Examination Survey, the Health and Welfare Survey, contact tracing, and several population surveillance systems of notifiable diseases.
However, the most significant difference between the information systems of developed and developing countries is the accuracy of routine statistics, particularly with respect to the cause of mortality. Thus, in Thailand, data collected for cause of death suffered from under-reporting. In addition, nearly half of the reported deaths were classified under ill-defined causes (Samutharaks et al. 1997). Even when deaths occur in hospitals, only a small percentage undergo autopsy (less than 10 per cent for large hospitals in Thailand). In some developed countries, linking records of repeat events occurring in individuals has been used to reduce the errors in recording the cause of deaths, dramatically reducing validity problems (Archeson 1966). As to the validity of morbidity data, even Western countries have variable notification of infection, with poorer notification for milder infection (Benjamin 1968). For diseases like cancer with a much longer natural history, most patients are likely to be registered.
The chief challenge of information systems in developed countries is how to ensure that the pressure of new but untested technology does not dictate the acquisition of high-technology equipment to track the operation of managed care. Recently, large budgets have been allotted to information systems in large health-care networks such as the Kaiser-Permanente’s Northern California Region ($1 billion over 7 years), Health Care Sacramento ($27.5 million over 5 years), and Sutler Health ($150 million over the next 7 years) (Morrissey 1995). How much the gain in health will mirror the extent of the increase in the efficiency of service delivery remains to be investigated. Moreover, there is a tendency for further investment in telemedicine and the expansion of fibre-optic capacity. This trend will complicate how information systems are used to track the allocation of resources and appropriate reimbursement for patient care. Whether the incremental increase in the investment in information systems will produce a proportional gain in health of the community is a valid and as yet unanswered question.
Developing countries must not be trapped into investing in high technology for sophisticated information systems beyond their needs. Some guidelines might be useful for decisions on the effective information system projects. Firstly, the involvement of the system users from the beginning is desirable for establishing a clear and realistic goal. Secondly, a complete review for existing solutions must be in place before deciding on investing in high technology. Thirdly, some assurance of adequate support and continuity from the vendor must be obtained since developing countries will be very dependent on the support system. Finally, the reality of the organizational constraints on the systems must be taken into account, for example, the adequacy of human resources to operate the system. Therefore, it is important to ‘think big’ (holistic manner), ‘start small’ (adopt an evolutionary not a ‘big bang’ approach), and ‘act rationally’ according to the need to advance the objectives of the health-care system (Wyatt 1994).
However, developing countries must invest in resources to capture essential information on health problems and trends (the resources used, utilization, costs, and outcomes of public health problems) to decide whether an investment in health care will yield the outcome described in the objectives of the health-care system. An information system is not for gathering information via sophisticated technology. It is for giving evidence to stakeholders to solve health problems with an accepted method of conflict resolution.

*The author wishes to acknowledge partial support by the Thailand Research Fund. The continuous support and encouragement of Professor Roger Detels is deeply appreciated.
Chapter References
Anonymous (1995). The World Health Organization quality of life assessment (WHOQOL): position paper from the World Health Organization. Social Science and Medicine, 41, 1403–9.
Archeson, R. (1966). Medical record linkage. Oxford University Press.
Asian Research Center for Migration (1999). Recent trends in international migration in Asia. Chulalongkorn University Printing House, Bangkok.
Bang, A.T. and Bang, R.A. (1992). Diagnosis of causes of childhood deaths in developing countries by verbal autopsy: suggested criteria. Bulletin of the WHO, 70, 499–507.
Benjamin, B. (1968). Health and vital statistics. Allen and Unwin, London.
Beyrer, C., Celentano, D.D., Suprasert, S., et al. (1997). Widely varying HIV prevalence and risk behaviours among the ethnic minority peoples of northern Thailand. AIDS Care, 9, 427–39.
Cassol, S., Weniger, B.G., Babu, P.G., et al. (1996a). Detection of HIV type 1 env subtypes A, B, C, and E in Asia using dried blood spots: a new surveillance tool for molecular epidemiology. AIDS Research in Human Retroviruses, 12, 1435–41.
Cassol, S.A., Read, S., Weniger, B.G., et al. (1996b). Dried blood spots collected on filter paper: an international resource for the diagnosis and genetic characterization of human immunodeficiency virus type-1. Memorias do Instituto Oswaldo Cruz, 91, 351–8.
Commission on Health Research for Development (1990). Health research: essential link to equity in development. Oxford University Press.
DeRiemer, K., Rudoy, I., Schecter, G.F., Hopewell, P.C., and Daley, C.L. (1999). The epidemiology of tuberculosis diagnosed after death in San Francisco, 1986–1995. International Journal of Tuberculosis and Lung Disease, 3, 488–93.
Dezateux, C. (1998). Evaluating newborn screening programmes based on dried blood spots: future challenges. British Medical Bulletin, 54, 877–90.
Frerichs, R.R. and Tar Tar, K. (1989). Computer-assisted rapid surveys in developing countries. Public Health Reports, 104, 14–23.
Frerichs, R.R., Silarug, N., Eskes, N., et al. (1994). Saliva-based HIV-antibody testing in Thailand. AIDS, 8, 885–94.
Ghana Health Assessment Project Team (1981). A quantitative method of assessing the health impact of different diseases in less developed countries. International Journal of Epidemiology, 10, 73–80.
Graubard, B.I. and Korn, E.L. (1999). Analyzing health surveys for cancer-related objectives. Journal of the National Cancer Institute, 91, 1005–16.
Henderson, R.H. and Sunaresan, T. (1982). Cluster sampling to assess immunization coverage: a review of experience with a simplified method. Bulletin of the WHO, 60, 253–60.
Hyder, A.A. and Morrow, R.H. (1998). Steady state assumptions in DALYs: effect on estimates of HIV impact. Journal of Epidemiology and Community Health, 53, 43–5.
Kilmarx, P.H., Limpakarnjanarat, K., Mastro, T.D., et al. (1998). HIV-1 seroconversion in a prospective study of female sex workers in northern Thailand: continued high incidence among brothel-based women. AIDS, 12, 1889–98.
Kitayaporn, D., Uneklabh, C., Weniger, B.G., et al. (1994). HIV-1 incidence determined retrospectively among drug users in Bangkok, Thailand. AIDS, 8, 1443–50.
Kitayaporn, D., Kaewkungwal, J., Bejrachandra, S., Rungroung, E., Chandanayingyong, D., and Mastro, T.D. (1996a). Estimated rate of HIV-1-infectious but seronegative blood donations in Bangkok, Thailand. AIDS, 10, 1157–62.
Kitayaporn, D., Tansuphaswadikul, S., Lohsomboon, P., et al. (1996b). Survival of AIDS patients in the emerging epidemic in Bangkok, Thailand. Journal of AIDS and Human Retrovirology, 11, 77–82.
Kitsiripornchai, S., Markowitz, L.E., Ungchusak, K., et al. (1998). Sexual behavior of young men in Thailand: regional differences and evidence of behavior change. Journal of AIDS and Human Retrovirology, 18, 282–8.
Kleinman, A. (1978). Culture, illness and care: clinical lessons from anthropology and cross cultural research. Annals of Internal Medicine, 88, 251–8.
Limpakarnjanarat, K., Ungchusak, K., Mastro, T.D., et al. (1998). The epidemiological evolution of HIV-1 subtypes B and E among heterosexuals and injecting drug users in Thailand, 1992–1997. AIDS, 12, 1108–9.
Limpakarnjanarat, K., Mastro, T.D., Saisorn, S., et al. (1999). HIV-1 and other sexually transmitted infections in a cohort of female sex workers in Chiang Rai, Thailand. Sexually Transmitted Infection, 75, 30–5.
Luepker, R.V. and Herlitz, J. (1999). Differences in the treatment of acute myocardial infarction between regions of countries and the impact on prognosis. Journal of Cardiovascular Risk, 6, 77–87.
Lumbiganon, P., Panamonta, M., Laopaiboon, M., Pothinam, S., and Patithat, N. (1990). Why are Thai official perinatal and infant mortality rates so low? International Journal of Epidemiology, 19, 997–1000.
MacQueen, K.M., Nopkesorn, T., Sweat, M.D., Sawaengdee, Y., Mastro, T.D., and Weniger, B.G. (1996). Alcohol consumption, brothel attendance, and condom use: normative expectations among Thai military conscripts. Medical Anthropology Quarterly, 10, 402–23.
Mastro, T.D. and Kitayaporn, D. (1998). HIV type 1 transmission probabilities: estimates from epidemiological studies. AIDS Research in Human Retroviruses, 14 (Supplement 3) S223–7.
Mastro, T.D. and Limpakarnjanarat, K. (1995). Condom use in Thailand: how much is it slowing the HIV/AIDS epidemic? AIDS, 9, 523–5.
Matloff, E.T., Shappell, H., Brierley, K., Bernhardt, B.A., McKinnon, W., and Peshkin, B.N. (2000). What would you do? Specialists’ perspectives on cancer genetic testing, prophylactic surgery and insurance discrimination. Journal of Clinical Oncology, 18, 2484–92.
Mills, S., Ungchusak, K., Srinivasan, V., Utomo, B., and Bennett, A. (1998). Assessing trends in HIV risk behaviors in Asia. AIDS, 12 (Supplement B), S79–86.
Ministry of Public Health (1997). Health in Thailand 1995–1996. Bureau of Health Policy and Planning. Ministry of Public Health, Nonthaburi.
Morrissey, J. (1995). Building networks to stay competitive. Modern Healthcare, August 21, 150–4.
Mulhall, B.P., Hu, M., Thompson, M., et al. (1993). Planned sexual behaviour of young Australian visitors to Thailand. Medical Journal of Australia, 158, 530–5.
Muller, O., Sarangbin, S., Ruxrungtham, K., Sittitrai, W., and Phanuphak, P. (1995). Sexual risk behaviour reduction associated with voluntary HIV counselling and testing in HIV infected patients in Thailand. AIDS Care, 7, 567–72.
Murray, C.J. and Lopez, A.D. (1996). The incremental effect of age-weighting on YLLs, YLDs, and DALYs: a response. Bulletin of the WHO, 74, 445–6.
Newbrander, W. (1997). Private health sector growth in Asia: issues and implications. Wiley, Chichester.
Nopkesorn, T., Mock, P.A., Mastro, T.D., et al. (1998). HIV-1 subtype E incidence and sexually transmitted diseases in a cohort of military conscripts in northern Thailand. Journal of AIDS and Human Retrovirology, 18, 372–9.
Peckham, C.S. and Dezateux, C. (1998). Issues underlying the evaluation of screening programmes. British Medical Bulletin, 54, 767–78.
Phoolcharoen, W. (1998). HIV/AIDS prevention in Thailand: success and challenges. Science, 280, 1873–4.
Phoolcharoen, W., Ungchusak, K., Sittitrai, W., and Brown, T. (1998). Thailand: lessons from a strong national response to HIV/AIDS. AIDS, 12 (Supplement B), S123–35.
Poshyachinda, V. (1993a). Drugs and AIDS in Southeast Asia. Forensic Science International, 62, 15–28.
Poshyachinda, V. (1993b). Drug injecting and HIV infection among the population of drug abusers in Asia. Bulletin of Narcotics, 45, 77–90.
Roberts, C.L., Tracy, S., and Peat, B. (2000). Rates for obstetric intervention amongst private and public patients in Australia: population-based descriptive study. British Medical Journal, 321, 137–41.
Rosomoff, H.L. and Rosomoff, R.S. (1999). Low back pain. Evaluation and management in the primary care setting. Medical Clinics of North America, 83, 643–62.
Samutharaks, B., Wecharak, P., Kongkamned, R., and Sitthi-amorn, C. (1997). Quantitative assessments of disease impact on society: a conceptual approach to prioritization and agenda setting of health problems for policy determination in Thailand. College of Public Health, Chulalongkorn University, Bangkok.
Sawanpanyalert, P., Ungchusak, K., Thanprasertsuk, S., and Akarasewi, P. (1994). HIV-1 seroconversion rates among female commercial sex workers, Chiang Mai, Thailand: a multi cross-sectional study. AIDS, 8, 825–9.
Shaffer, N., Roongpisuthipong, A., Siriwasin, W., et al. (1999). Maternal virus load and perinatal human immunodeficiency virus type 1 subtype E transmission, Thailand. Bangkok Collaborative Perinatal HIV Transmission Study Group. Journal of Infectious Disease, 179, 590–9.
Siriwasin, W., Shaffer, N., Roongpisuthipong, A., et al. (1998). HIV prevalence, risk, and partner serodiscordance among pregnant women in Bangkok. Bangkok Collaborative Perinatal HIV Transmission Study Group. Journal of the American Medical Association, 280, 49–54.
Sitthi-amorn, C., Chandraprasert, S., Bunnag, S.C., and Plengvidhya, C.S. (1989). The prevalence and risk factors of hypertension in Klong Toey slum and Klong Toey government apartment houses. International Journal of Epidemiology, 18, 89–94.
Smith, G.S. (1989). Development of rapid epidemiological assessment methods to evaluate health status and delivery of health services. International Journal of Epidemiology, 19 (Supplement 4).
Snow, B. and Marsh, K. (1992). How useful are verbal autopsies to estimate childhood causes of death? Health Policy and Planning, 7, 22–9.
Stephenson, J.M. (1998). Screening for genital chlamydial infection. British Medical Bulletin, 54, 891–902.
Suwanagool, S., Chaiyakul, P., Ratanasuwan, W., Pechthanom, L., and Chaisilwattana, P. (1995). HIV-1 infection among low income women attending a Siriraj sexually transmitted disease clinic: sociodemographic differentials. Journal of the Medical Association of Thailand, 78, 355–61.
Ungchusak, K., Rehle, T., Thammapornpilap, P., Spiegelman, D., Brinkmann, U., and Siraprapasiri, T. (1996). Determinants of HIV infection among female commercial sex workers in northeastern Thailand: results from a longitudinal study. Journal of AIDS and Human Retrovirology, 12, 500–7. (Erratum Journal of AIDS and Human Retrovirology, 18, 192 (1998)).
Van Griensven, G.J., Limanonda, B., Ngaokeow, S., Ayuthaya, S.I., and Poshyachinda, V. (1998). Evaluation of a targeted HIV prevention programme among female commercial sex workers in the south of Thailand. Sexually Transmitted Infection, 74, 54–8.
Vanichseni, S., Des Jarlais, D.C., Choopanya, K., et al. (1993). Condom use with primary partners among injecting drug users in Bangkok, Thailand and New York City, United States. AIDS, 7, 887–91.
Van Landingham, M., Grandjean, N., Suprasert, S., and Sittitrai, W. (1997). Dimensions of AIDS knowledge and risky sexual practices: a study of northern Thai males. Archives of Sexual Behaviour, 26, 269–93.
Wadswarth, M.I., Butterfield, B.J.H., and Blaney, R. (1971). Health and sickness: the choice of treatment. Tavistock Publications, London.
WHO (World Health Organization) (2000a). The world health report 2000: health systems—improving performance. WHO, Geneva.
WHO (World Health Organization) (2000b). The world health report on infectious diseases. WHO, Geneva.
Wyatt, J.C. (1994). Clinical data systems. 3. Developing and evaluating clinical data systems. Lancet, 344, 1682–8.

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