Severe malaria among children in a low seasonal transmission area, Dakar, Senegal: influence of age on clinical presentation.

The influence of age on the clinical presentation of severe malaria and especially on its 2 most commonly encountered manifestations, cerebral malaria and severe anaemia, has been retrospectively examined in 161 children (< 16 years old) admitted to the paediatric department of Hôpital Principal de Dakar from 1 January 1990 to 29 February 1996. They lived in Dakar and its suburbs, a region of Senegal where the malaria transmission rate is very low. Cases were defined by at least one of the World Health Organization criteria of severe malaria and the presence of Plasmodium falciparum in blood smears. Severe anaemia was present in 73.1%, 52.1% and 26.2% cases of severe malaria among children aged 0-3 years, 4-7 years and 8-15 years, respectively (P < 0.0001). The frequency of cerebral malaria was 11.3%, 28.2% and 60.6%, respectively, in the same age groups (P < 0.0001). Severe anaemia and cerebral malaria were associated in 8.7% of the cases of severe malaria. The fatality rate was significantly lower in cases of severe anaemia without cerebral malaria (3%) than in cases of cerebral malaria without severe anaemia (17.5%; P < 0.02). Among young children, severe anaemia was associated with brief hyperparasitaemia or with prolonged lower parasitaemia. Other things being equal, older children had a lower risk of severe anaemia. The results suggest that the high prevalence of severe anaemia in young children, even in an area of very low endemicity, depends more on age and parasitaemia than on the transmission level.