[Comparative evaluation of the plasmodial infection of Anopheles using ELISA and dissection. Consequences for the estimation of the transmission of malaria in 1995 in Ndiop, Senegal].

An entomological study was carried out in Ndiop village, Senegal, an area of sudan-type savana, from January to December 1995, to compare the malaria inoculation rate measured by the dissection of salivary glands of anophelines and the enzyme-linked immunosorbent assay (ELISA). Mosquitoes were sampled by night-bite collections. Species from the Anopheles gambiae complex were identified using the polymerase chain reaction. 1292 females Culicidae were collected. 597 anophelines mosquitoes known to be malaria vectors were captured during 148 man-nights of capture. Of the 572 anophelines investigated, 14 were positive using dissection while 21 were found to be positive with ELISA. The sporozoite rates were 2.5%, 2.2% and 3.8% for An. arabiensis, An. gambiae and An. funestus, respectively. The circumsporozoite rates were 3.5%, 2.2% and 7.7% for these three species, respectively. ELISA detected 1.5 times more positive mosquitoes than dissection. These results are discussed with reference to the duration of the sporogonic cycle, the delay before CSP antigens are apparent, and the daily survival rate of Anopheles mosquitoes.