Behavior of Wuchereria bancrofti (Filariidea: Onchocercidae) infective larvae in the vector Aedes polynesiensis (Diptera:Culicidae) in relation to parasite transmission.

In French Polynesia, Aedes polynesiensis Marks is the major vector of human filariasis caused by subperiodic Wuchereria bancrofti (Cobbold). Factors affecting transmission of infective larvae from vector to humans were assessed. The 66-100% loss of infective larvae during a blood meal was independent of the initial vector parasite burden. Infective larvae were able to migrate to the mouthparts during a blood meal. Blood feeding by mosquitoes to repletion was one important aspect in the escape of larvae. Infective larvae were not transmitted (lost) without a blood meal and may move in the vector's body. Ae. polynesiensis may retain infectivity potential during several days and may infect several hosts during one blood meal session or on several gonotrophic cycles. In terms of parasite transmission, these findings were interpreted as efficient adaptations of the filaria to the Ae. polynesiensis biting habits.