The fate of Plasmodium gallinaceum in Anopheles stephensi Liston and possible barriers to transmission.

Plasmodium gallinaceum develops up to the ookinete stage in the non-compatible mosquito, Anopheles stephensi, this development occurring over the same time period and with the same success as in the compatible vector, Aedes aegypti. The slower digestive rate in An. stephensi, smaller blood-meal and lower enzyme activity than in Aedes, and an acceleration of the formation of the peritrophic membrane (PM) do not inhibit the development of the parasite. However, the ookinetes are not able to penetrate the midgut epithelium. The role of blood, vector and parasite in establishing a parasite infection in the mosquito are all considered. In particular, the role of vector-parasite recognition mechanisms in determining vector-parasite specificity are discussed.