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Childhood Mortality In Rural Senegal: A Significant Decline But Danger Of Resurgence Persists

September 27, 2002

The childhood death rate in sub-Saharan Africa is one of the highest in the world, in spite of a decline observed over the past few decades. This trend had been analysed for short selected periods, but the factors determining it over the long term are poorly known, owing to insufficient data.

Demographic surveillance has been conducted in African towns and cities over several decades, but in rural areas, statistics are much more scarce.
IRD has since 1962 been monitoring demographic trends in the rural district of Niakhar, 135 km west of Dakar. People living in this zone had limited incomes and their level of education was minimal. As many as 40% had no access to running water, often the case in rural West Africa.

Researchers used data collected over a 12 year period, from 1987 to 1999, from a sample of 30 villages in the district (representing 30 000 people) and focused on 8 of them (6000 people) to determine the trend over more than 30 years. Most causes of death were identified using medical history questionnaires. Other sources, such as pregnancy follow-up records, provided complementary data to this epidemiological information to give a fuller picture. Data were recorded continuously to a degree of accurate detail seldom achieved in Africa. They gave the basis for a fine-tuned analysis of population changes.

The epidemiological analysis showed that infant and child death rate declined markedly and steadily between 1963 and 1999, except for isolated peaks provoked by cholera or cerebrospinal meningitis epidemics. Mortality in infants (less than 1 year) fell by 64% (from 223 to 80"°), and in under 5s, by 56% (from 485 to 213"°). The most striking change is seen in the age distribution of deaths. A strong improvement occurred among infants between 6 and 24 months (decrease from 321 to 87"°) during the 1970s. The study highlights also how a seasonal peak usually appearing in the rainy period between July and October, damped down until the 1980s, but then reappeared in the figures in the 1990s.

Vaccination has been a major factor in bringing mortality down and in age distribution changes. Intense campaigns conducted in 1978 and 1982, followed by an even wider-reaching programme from the 1980s, dramatically reduced particularly deadly diseases like measles, whooping cough and tetanus. The decrease from the 1960s to 1980s in the number of deaths during the rainy season, when infants of 6 to24 months area severely exposed to infectious diseases and malnutrition, would also be the effect of vaccination and malaria-control campaigns. Socio-economic development and improvement in sanitary conditions have certainly also played their part in lowering child mortality. Their role is, however, more difficult to quantify.

But the situation is still causing concern, in spite of the improvement seen since the early 1960s. Some surveys indicate fewer children were vaccinated in the 1990s and that seasonal increases of mortality are a re-emerging trend. These deaths are attributed to malaria and to the rising resistance to chloroquine. In addition, Senegal has been hit recently by a cerebrospinal meningitis epidemic. Aids is spreading in many sub-Saharan African countries, but it appears to have spared this population thus far.

If the trend of declining childhood mortality is to continue, vaccination programmes and malaria control campaigns must be reinforced or revised. Epidemiologists recommend prevention and control strategies against potential epidemic disease (cholera, meningitis). In the longer term, access to family planning and high-standard obstetrical care will also help to reduce perinatal and infant mortality.

Institut de Recherche pour le Développement, Paris (IRD)