Studies on the use of a membrane feeding technique for infecting Anopheles gambiae with Plasmodium falciparum.

An investigation was made of the optimum feeding time when using stirred membrane feeders for infecting Anopheles gambiae s.s. with Plasmodium falciparum. The aim was to stimulate the natural situation of direct feeding on a host and so enable the malaria susceptibility of different populations of A. gambiae to be assessed. 45 feeds were carried out on blood donated by P. falciparum gametocyte carriers. The results show that only patients with at least 300 gametocytes/mm3 are likely to produce a high infection in mosquitoes. There was a marked decline in infectivity over a 35-min period after bleeding and 10-min feeds gave the highest proportion of mosquitoes infected. The decline in infectivity could not be attributed solely to the fact that the gametocytes had become activated before ingestion by the mosquito, since the rate of activation in a feeder was found to be lower than the rate of loss of infectivity to mosquitoes. The possible applications of the technique are discussed.