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Thursday, 17 March 2011 18:11

Surveillance in Developing Countries

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It is estimated that more than 80% of the world’s population live in the developing countries in Africa, the Middle East, Asia and South and Central America. The developing countries are often financially disadvantaged, and many have largely rural and agricultural economies. However, they are widely different in many ways, with diverse aspirations, political systems and varying stages of industrial growth. The status of health among people in the developing countries is generally lower than in the developed countries, as reflected by higher infant mortality rates and lower life expectancies.

Several factors contribute to the need for occupational safety and health surveillance in developing countries. First, many of these countries are rapidly industrializing. In terms of the size of industrial establishments, many of the new industries are small-scale industries. In such situations, safety and health facilities are often very limited or non-existent. In addition, developing countries are often the recipients of technology transfer from developed countries. Some of the more hazardous industries, which have difficulty in operating in countries with more stringent and better enforced occupational health legislation, may be “exported” to developing countries.

Second, with regard to the workforce, the education level of the workers in developing countries is often lower, and workers may be untrained in safe work practices. Child labour is often more prevalent in developing countries. These groups are relatively more vulnerable to health hazards at work. In addition to these considerations, there is generally a lower pre-existing level of health among workers in developing countries.

These factors would ensure that throughout the world, workers in developing countries are among those who are most vulnerable to and who face the greatest risk from occupational health hazards.

Occupational Health Effects are Different from Those Seen in Developed Countries

It is important to obtain data on health effects for prevention and for prioritization of approaches to solve occupational health problems. However, most of the available morbidity data may not be applicable for developing countries, as they originate from the developed countries.

In developing countries, the nature of the occupational health effects from workplace hazards may be different from those in the developed countries. Overt occupational diseases such as chemical poisonings and the pneumoconioses, which are caused by exposures to high levels of workplace toxins, are still encountered in significant numbers in developing countries, while these problems may have been substantially reduced in the developed countries.

For example, in the case of pesticide poisoning, acute health effects and even deaths from high exposures are a greater immediate concern in developing agricultural countries, as compared to the long-term health effects from low dose exposure to pesticides, which might be a more important issue in the developed countries. In fact, the morbidity burden from acute pesticide poisoning in some developing countries, such as Sri Lanka, may even surpass that of traditional public health problems such as diphtheria, whooping cough and tetanus.

Thus, some surveillance of occupational health morbidity is required from the developing countries. The information would be useful for the assessment of the magnitude of the problem, prioritization of plans to cope with the problems, allocation of resources and for subsequent evaluation of the impact of interventions.

Unfortunately, such surveillance information is often lacking in the developing countries. It should be recognized that surveillance programmes in developed countries may be inappropriate for developing countries, and such systems probably cannot be adopted in their entirety for developing countries because of the various problems which may impede surveillance activities.

Problems of Surveillance in Developing Countries

While the need for surveillance of occupational safety and health problems exists in developing countries, the actual implementation of surveillance is often fraught with difficulties.

The difficulties may arise because of poor control of industrial development, the absence of, or an inadequately developed infrastructure for, occupational health legislation and services, insufficiently trained occupational health professionals, limited health services and poor health reporting systems. Very often the information on the workforce and general population may be lacking or inadequate.

Another major problem is that in many developing countries, occupational health is not accorded a high priority in national development programmes.

Activities in Occupational Health and Safety Surveillance

Surveillance of occupational safety and health may involve activities such as the monitoring of dangerous occurrences at work, work injury and work fatalities. It also includes surveillance of occupational illness and surveillance of the work environment. It is probably easier to collect information on work injury and accidental death at work, since such events are fairly easily defined and recognized. In contrast, surveillance of the health status of the working population, including occupational diseases and the state of the work environment, is more difficult.

The rest of this article will therefore deal mainly with the issue of surveillance of occupational illness. The principles and approaches which are discussed can be applied to the surveillance of work injuries and fatalities, which are also very important causes of morbidity and mortality among workers in developing countries.

Surveillance of workers’ health in developing countries should not be limited only to occupational diseases, but should also be for general diseases of the working population. This is because the main health problems among workers in some developing countries in Africa and Asia may not be occupational, but may include other general diseases such as infectious diseases—for example, tuberculosis or sexually transmitted diseases. The information collected would then be useful for planning and allocation of health care resources for the promotion of health of the working population.

Some Approaches to Overcome the Problems of Surveillance

Which types of occupational health surveillance are appropriate in developing countries? In general, a system with simple mechanisms, employing available and appropriate technology, would be best suited for developing countries. Such a system should also take into account the types of industries and work hazards which are important in the country.

Utilization of existing resources

Such a system may utilize the existing resources such as the primary health care and environmental health services. For example, occupational health surveillance activities can be integrated into the current duties of primary health care personnel, public health inspectors and environmental engineers.

For this to happen, primary health care and public health personnel have first to be trained to recognize illness which may be related to the work, and even to perform simple assessments of unsatisfactory workplaces in terms of occupational safety and health. Such personnel should, of course, receive adequate and appropriate training in order to perform these tasks.

The data on conditions of work and illness arising from work activities can be collated while such persons conduct their routine work in the community. The information collected can be channelled to regional centres, and ultimately to a central agency responsible for the monitoring of conditions of work and occupational health morbidity that is also responsible for acting on these problems.

Registry of factories and work processes

A registry of factories and work processes, as opposed to a disease registry, could be initiated. This registry would obtain information from the registration stage of all factories, including work processes and materials used. The information should be updated periodically when new work processes or materials are introduced. Where, in fact, such registration is required by national legislation, it needs to be enforced in a comprehensive manner.

However, for small-scale industries, such registration is often bypassed. Simple field surveys and assessments of the types of industry and the state of working conditions could provide basic information. The persons who could perform such simple assessments could again be the primary health care and public health personnel.

Where such a registry is in effective operation, there is also a need for periodic update of the data. This could be made compulsory for all registered factories. Alternatively, it may be desirable to request an update from factories in various high-risk industries.

Notification of occupational diseases

Legislation for notification of selected occupational health disorders could be introduced. It would be important to publicize and educate people on this matter before implementation of the law. Questions such as what diseases should be reported, and who should be the persons responsible for notification, should first be resolved. For example, in a developing country like Singapore, physicians who suspect the occupational diseases listed in table 1 have to notify the Ministry of Labour. Such a list has to be tailored to the types of industry in a country, and be revised and updated periodically. Furthermore, the persons responsible for notification should be trained to recognize, or at least to suspect, the occurrence of the diseases.

Table 1. Sample list of notifiable occupational diseases

Aniline poisoning

Industrial dermatitis


Lead poisoning

Arsenical poisoning

Liver angiosarcoma


Manganese poisoning


Mercurial poisoning

Beryllium poisoning



Noise-induced deafness

Cadmium poisoning

Occupational asthma

Carbon disulphide poisoning

Phosphorous poisoning

Chrome ulceration


Chronic benzene poisoning

Toxic anaemia

Compressed air illness

Toxic hepatitis


Continuous follow-up and enforcement action is needed to ensure the success of such notification systems. Otherwise, gross underreporting would limit their usefulness. For example, occupational asthma was first made notifiable and compensable in Singapore in 1985. An occupational lung disease clinic was also set up. Despite these efforts, a total of only 17 cases of occupational asthma were confirmed. This can be contrasted with the data from Finland, where there were 179 reported cases of occupational asthma in 1984 alone. Finland’s population of 5 million is only about twice that of Singapore. This gross under-reporting of occupational asthma is probably due to the difficulty in diagnosing the condition. Many doctors are unfamiliar with the causes and features of occupational asthma. Hence, even with the implementation of compulsory notification, it is important to continue to educate the health professionals, employers and employees.

When the notification system is initially implemented, a more accurate assessment of the prevalence of the occupational disease can be made. For example, the number of notifications of noise-induced hearing loss in Singapore increased six-fold after statutory medical examinations were introduced for all noise-exposed workers. Subsequently, if the notification is fairly complete and accurate, and if a satisfactory denominator population could be obtained, it may even be possible to estimate the incidence of the condition and its relative risk.

As in many notification and surveillance systems, the important role of notification is to alert the authorities to index cases at the workplace. Further investigations and workplace interventions, if necessary, are required follow-up activities. Otherwise, the efforts of notification would be wasted.

Other sources of information

Hospital and outpatient health information is often underutilized in the surveillance of occupational health problems in a developing country. Hospitals and outpatient clinics can and should be incorporated into the notification system for specific diseases, such as acute work-related poisonings and injuries. The data from these sources would also provide an idea of the common health problems among workers, and can be used for the planning of workplace health promotion activities.

All this information is usually routinely collected, and few extra resources are required to direct the data to the occupational health and safety authorities in a developing country.

Another possible source of information would be the compensation clinics or tribunals. Finally, if the resources are available, some regional occupational medicine referral clinics might also be initiated. These clinics could be staffed by more qualified occupational health professionals, and would investigate any suspected work-related illness.

Information from existing disease registries should also be utilized. In many larger cities of developing countries, cancer registries are in place. Though the occupational history obtained from these registries may not be complete and accurate, it is useful for preliminary monitoring of broad occupational groups. Data from such registries will be even more valuable if registers of workers exposed to specific hazards are available for cross-matching.

The role of data linkage

While this may sound attractive, and has been employed with some success in some developed countries, this approach may not be appropriate or even possible in developing countries at present. This is because the infrastructure required for such a system is often not available in developing countries. For example, disease registries and workplace registers may not be available or, if they exist, may not be computerized and easily linked.

Help from international agencies

International agencies such as the International Labour Organization, the World Health Organization and bodies such as the International Commission on Occupational Health can contribute their experience and expertise in overcoming common problems of occupational health and safety surveillance in a country. In addition, training courses as well as training opportunities for primary care persons may be developed or offered.

Sharing of information from regional countries with similar industries and occupational health problems is also often useful.


Occupational safety and health services are important in developing countries. This is especially so in view of the rapid industrialization of the economy, the vulnerable work population and the poorly controlled health hazards faced at work.

In the development and delivery of occupational health services in these countries, it is important to have some type of surveillance of occupational ill health. This is necessary for the justification, planning and prioritization of occupational health legislation and services, and the evaluation of the outcome of these measures.

While surveillance systems are in place in the developed countries, such systems may not always be appropriate for developing countries. Surveillance systems in developing countries should take into account the type of industry and hazards which are important in the country. Simple surveillance mechanisms, employing available and appropriate technology, are often the best options for developing countries.



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