DEFINITION OF POPULATIONS AT RISK FOR PLASMODIUM-FALCIPARUM INFECTION IN 3 ENDEMIC AREAS OF CAMEROON

Blood samples were collected from 285 individuals attending hospitals in 1 of 3 different regions of Cameroon. Of these, 89 had Plasmodium falciparum parasitemia. Prevalence in the Douala region was drastically reduced above the age of 19. In the Njinikom and Bamenda regions, on the other hand, an appreciable decline in prevalence was not observed until over the age of 49. Enzyme-linked immunosorbent assay (ELISA) values indicate that in Douala, high antibody titers to P. falciparum were present in all age groups tested. In Njinikom and Bamenda, an age dependence was seen in the response, with sera from individuals above 20 having significantly higher ELISA values compared with those below age 20. Generally, individuals with high antibody titers had low or no parasitemia. Results suggest that future malaria control and treatment measures might target high risk populations such as those defined in this study.