Melanization of Dirofilaria immitis Larvae in Different Culicid Species

Dirofilaria immitis is an important filarioid transmitted by culicids. The vector role of these arthropods may be influenced by biological events as melanization against D. immitis larvae. This study aimed to detect the occurrence of melanization in Culex quinquefasciatus, Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus experimentally infected with D. immitis.

Five populations (Cx. quinquefasciatus RECIFE (P1), Ae. albopictus RECIFE (P2), Ae. aegypti RECIFE (P3), Ae. aegypti CAMPINAS (P4) and Ae. aegypti ROCKEFELLER (P5)) were artificially fed with infected blood containing D. immitis microfilariae. Ten mosquitoes per day from each population were dissected for 14 days.

Melanized larvae of D. immitis were observed in all population except in P3. The period in which melanized larvae were found varied from the third to the 14th day post-infection. Difference in the number of these larvae was observed between P5 and P2–P3 (P

The melanization did not seem to be a limiting factor to the development of this filarioid in these local Brazilian Culicidae populations.