[Infectivity of Anopheles melas vis-a-vis Plasmodium falciparum in the coastal lagoon area of Benin]

Abstract

In this article An. melas infestation rate for P. falciparum is compared to the rate of An. gambiae in the coastal and lagoon area of Benin where the two species are sympatric. We studied the variation of An. gambiae complex infestation rate in three zones where the two species occur in different proportions. This infestation rate is higher in areas where An. gambiae is prevalent. In a second experiment we separated An. melas and An. gambiae according to cytogenetic and biometrical analysis. Then we established the infestation rate of each species by microscope examination of salivary glands and presence of P. falciparun C.S. antigens by ELISA method. In areas where An. melas is the most abundant species (80-90%), the sporozoitic index and antigen C.S. + P. falciparum rate are significantly lower. These results are confirmed by the infestation rates observed for each species. In conclusion, An. melas infestation rate is significantly lower than the An. gambiae one. An. gambiae is the best malaria vector in Africa. In spite of an environment such as Ganvie where animals are rare, which increases anthropophilic and endophilic tendencies of An. melas, antigens CS P. falciparum rate of An. gambiae (3.5%) are significantly higher than An. melas (1.9%).