PLASMODIUM OVALE IN A HIGHLY MALARIA ENDEMIC AREA OF SENEGAL

During 4 months, from June to September 1990, the population of Dielmo village, Senegal, an area of intense and perennial malaria transmissi on, was enrolled in a follow-up study including daily clinical surveil lance and bi-weekly malaria parasitaemia monitoring. Thick blood film examinations indicated that: 48.5% of children (49/101) and 32.4% of a dults (34/105) were infected at least once by Plasmodium ovale during the study period; 148 distinct episodes of patent parasitaemia were ob served, with estimated maximum durations of 3-115 d. The mean duration at first decreased significantly with age, from 11.4 d in children un der 5 years old to 4.2 d in adults aged 40-59 years, but then increase d in older adults to 7.0 d. In all age groups, most infections were as ymptomatic. Only high parasitaemias were significantly associated with fever; 3 clinical malaria attacks due to P. ovale were seen during th e study period.