Children's environmental health

Disease vectors

Malaria is rampant in Sub-Saharan Africa and many countries in Asia and Latin America, where children under five suffer high mortality and morbidity. In older children, malaria remains an important cause of mortality and morbidity and significantly contributes to low educational achievement. Malaria exists in 100 countries and accounts for more than 1 million deaths annually, mostly in children under five (World Health Report 2003, WHO). About 90% of the disease burden resides in Africa

Young girl in country side
Photo: Fiona Gore, WHO

Schistosomiasis is a water-borne disease that affects children and adolescents mainly because of their specific behaviours: lack of hygiene and swimming in contaminated water. It is endemic in 74 developing countries, with more than 80% of infected people living in Sub-Saharan Africa. High infection rates and individual worm loads set the scene for a debilitating infection which may cause severe damage to the liver or bladder over many years, and can result in premature death.

Japanese encephalitisoccurs only in South and South-east Asia, where it is linked with irrigated rice production ecosystems. Outbreaks occur in cycles. The annual number of clinical cases is estimated at about 40 000. Some 90% of these cases are children in rural areas, with a 20% case-fatality rate.

Dengue affects mainly urban populations (the Aedes species that transmit dengue are adapted to the man-made environment), and in children the infection can develop into dengue haemorrhagic fever or dengue shock syndrome with high levels of mortality. Annually, mortality due to dengue fever is estimated at around 13 000; more than 80% of these deaths occur in children. A combination of five interventions in different settings is proposed for the mosquito-borne diseases: use of insecticideimpregnated mosquito nets; the fitting of screens to windows, doors and eaves of houses; the application of zooprophylaxis in places where mosquitoes are distinctly zoophilic; the use of insect repellents; and improved water management. For the control of schistosomiasis, case detection and drug treatment proved to be most cost-effective in the short term, but as prevalence levels drop it becomes increasingly expensive to keep them low. Enhanced environmental management, provision of basic sanitation and community health education should be put into place to make the achievement of drug treatment sustainable.

Taking action

Sound and sustainable approaches to controlling disease vectors, and integrated prevention strategies should be put in place. This requires increased research into the development of safe alternative pesticides, and on alternative approaches such as biological control and integrated vector management. The use of such approaches should be promoted at community level. Decision making criteria and procedures for community-based interventions should be developed, with the aim of reducing the transmission risk in specific agricultural ecosystems.

Efforts should build on existing programmes for vector-borne disease control. In the case of malaria, collaboration with the Roll Back Malaria (RBM) programme on rapid assessment of the malaria situation, on promoting the use of bednets and chemoprophylaxis, and on developing zooprophylaxis for malaria control in rice irrigation schemes offers opportunities in this respect.

Given the importance of personal behaviours for prevention of vector-borne diseases, education on hygiene practices and behaviours among parents, child care-givers and children should be provided. Safe domestic water management should be promoted with the aim of reducing dengue risk.