Variation in the vector competence of Aedes polynesiensis for Wuchereria bancrofti

The vector competences of 6 geographic strains of Aedes polynesiensis for Wuchereria bancrofti were studied using two types of experimental infections. Experimental infection of laboratory-bred mosquitoes fed on the carriers' forearms with different levels of microfilaraemia showed that microfilariae (mf) uptake was directly proportional to the carrier's mf density and, as mf densities decreased, concentration capacity of Ae. polynesiensis increased. It was also shown that infection has an important effect on mosquito mortality, and that the mortality rate differed among mosquito strains. In infections using artificial feeders, the mf uptake was closely regulated, thus showing differences in the vectorial efficiency of Ae. polynesiensis related to the geographic origin of the mosquito strain. The mosquitoes from the Society archipelago were more efficient intermediate hosts than geographically distant strains when infected with W. bancrofti from an island within the archipelago (Tahiti). Mosquito strains from the Society archipelago developed the highest proportion of infective-stage larvae and exhibited the lowest mortality rate when infected with sympatric Tahitian W. bancrofti.