Factors influencing the development of Brugia pahangi microfilariae on Culex quinquefasciatus and Aedes aegypti mosquitoes
Culex quinquefasciatus (Wiedemann) mosquitoes, which are refractory to Brugia pahangi (Buckley and Edeson) microfilariae, were fed simultaneously on Wuchereria bancrofti (Cobbold) and B. pahangi microfilariae. A selected stock of Aedes aegypti (L) which is susceptible to both of these filariae was used as a control. The exsheathment and migration rates of B. pahangi in C. quinquefasciatus increased significantly as compared to those of B. pahangi when given as a feed by itself. These two processes did not show any trend with time. On dissection, 12 and 14 days postinfection, 27% of C. quinquefasciatus were found to be infected with an average of two larvae per mosquito. Of the total number of larvae found 78% were W. bancrofti while 22% were B. pahangi. Feeding C. quinquefasciatus on in vitro exsheathed B. pahangi microfilariae suspended in serum did not increase the rate of migration, whereas 71–100% of Ae. aegypti became infected with a mean of 3.5 larvae per mosquito. Inoculation of C. quinquefasciatus mosquitoes into the thorax and abdomen with exsheathed B. pahangi did not increase their infection rate, whereas in Ae. aegypti 67–82% became infected.