FILARIA VECTOR COMPETENCE OF SOME ANOPHELES SPECIES

The filaria vector competence of Anopheles stephensi was compared with Brugia - susceptible Aedes aegypti Liverpool strain, An. gambiae Bada gry Lagos strain and An. dirus Perlis Malaysia strain. An. stephensi i ngested more Brugia pahangi microfilariae, had the highest infectivity rate and yielded more infective mosquitoes than the other two anophel ine species. The overall vector competence of An. stephensi was 0.13 t imes that of Ae. aegypti, 0.62 times that of An. gambiae and 2.17 time s that of An. dirus. However, heavy mortality among infected An. steph ensi in the present investigation indicates that the filaria vectorial capacity of the mosquito might be limited epidemiologically. The rela tionship between filaria vector competence and mosquito foregut armatu re is discussed. It was observed that the relative Vector competence o f the three anopheline species tested was in the same order as their r elative degrees of armature elaboration. The converse would be expecte d if foregut armatures really give partial protection to the mosquitoe s against filarial infection. It is suggested that high host microfila riae density favours larval survival proportional to the degree of arm ature development in Anopheles (Cellia) species.