Factors influencing the development of Brugia pahangi Microfilariae in Culex quinquefasciatus and Aedes aegypti Mosquitoes

Abstract

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. Culex quinquefasciatus (Wiedemann), ces moustiques qui sont refractaires aux microfilaires du Brugia pahangi ont ete nourris simultanement avec des microfilaires du Wuchereria bancrofti (Cobbold) et du B. pahangi. Pour controler, une ligne selectionnee d’Aedes aegypti, sensibles a ces deux filiaires, a ete utilisee. Les taux de mue et de migration du B. pahangi dans les C. quinquefasciatus ont augmente d’une maniere plus significative que ceux des B. pahangi alimentes en Wuchereria bancrofti. Ces deux procedes n’ont rien demontre. Lors de la dissection des jours 12 et 14 postinfection, 27% des C. quinquefasciatus ont ete infectes avec une moyenne de 2 larves par moustiques. 78% du nombre total des larves trouvees furent des W. bancrofti tandis que 22% etaient des B. pahangi. Alimenter in vitro les C. quinquefasciatus avec les microfiiaires decouverts, baignant dans le serum n’a pas augmente le taux de migration alors que 71 % des Ae. aegypti devinrent infectes a raison de 3.5 larves par moustique. L’innoculation de B. pahangi mues dans le thorax et abdomen des moustiques C. quinquefasciatus, n’a pas augmente leur taux d’infection, tandis que dans l’Ae. aegypti 67.82% devinrent infectes.