Severity of imported falciparum malaria: effect of taking antimalarial prophylaxis.

OBJECTIVE To investigate the effects of antimalarial chemoprophylaxis and other variables on the severity of falciparum malaria. DESIGN Review of consecutive malaria cases between 1987 and 1991. SETTING The Hospital for Tropical Diseases, London. SUBJECTS 250 consecutive cases of mild and 51 consecutive cases of severe falciparum malaria. RESULTS Prophylaxis was taken in 52.4% (131/250) of the cases of mild malaria and 21.6% (11/51) of cases of severe malaria. Severe malaria was more common in white patients than in those of African origin and was also seen more commonly in people returning from central, southern, and east Africa than in those returning from west Africa. Patients with severe malaria presented sooner than patients with mild malaria. CONCLUSIONS Prior chemoprophylaxis led to a reduction in the severity of falciparum malaria. Ethnic origin, time to presentation, and sex were also associated with the severity of malaria.