Decline of infant and child mortality rates in rural Senegal over a 37-year period (1963-1999)

Background In spite of an improving trend, childhood mortality in rural sub-Saharan Africa remains high and has recently risen in some countries. The factors associated with the long-term decline in childhood mortality are poorly known, due to a lack of data. Methods A Senegalese rural population has been under demographic surveillance since 1963. Infant and under-5 mortality rates were calculated for different periods to generate a long-term trend in childhood mortality. Evolution of age and seasonal patterns of mortality were observed. Findings During the observation period (1963-1999), infant and under-5 mortality rates decreased from 223parts per thousand to 80parts per thousand and 485parts per thousand to 213parts per thousand, respectively, with a constant annual rate of decline in the probability of dying since the 1960s (-3.7% and-3.1%, respectively). The age pattern of the under-5 mortality changed drastically, with a large decrease in the death rate between 6 and 24 months of age (from 321parts per thousand. to 87parts per thousand). This Change took place during the 1970s. The seasonal variation, characterized by a greater proportion of deaths during the rainy season, was very marked during the 1960s, then decreased during the 1980s but it has tended to increase again in the 1990s, particularly among children 1-4 years old. Conclusion This study confirms the long-term trend of decrease in child mortality in rural West Africa. Historical knowledge on healthcare developments suggests that immunizations have, contributed to the decrease and the change in the age pattern. The re-emergence of malaria seems the most likely explanation for the recent rebound in seasonal variation. Attention to immunization and malaria should continue to be a priority.