Evaluation of larval development of Dirofilaria immitis in different populations of Aedes aegypti and Aedes albopictus.

Abstract

Dirofilaria immitis is an important nematode parasite commonly known as heartworm. This filarioid is transmitted by culicid vectors and primarily affects dogs, but other animals may also become infected, such as wild carnivores, cats and humans. The aim of the present study was to assess the development of D. immitis larvae in different culicid populations under laboratory conditions. Adult females of populations of Aedes aegypti from the city of Recife (P1), the city of Campinas (P2) and the Rockefeller strain from the Centers for Disease Control (P3) and one population of Aedes albopictus from Recife (P4) were fed for two hours with infected dog blood containing 2,000 microfilariae/ml of D. immitis. After artificial feeding, the specimens were maintained under controlled conditions. Ten females from each population were dissected daily over 14 days. The infection ratio and vector efficiency index were calculated and D. immitis development from L1 to L3 was assessed. The larvae in P1, P2, P3 and P4 reached the third stage in 11, 10, 14 and 9 days, respectively. The vector efficiency index was 53.8%, 20.0%, 7.4% and 25.2% in P1, P2, P3 and P4, respectively. The findings demonstrate that D. immitis larvae develop in all culicid populations studied herein. Based on mosquito mortality, development time and VEI the A. albopictus population from Recife (P4) demonstrated the best performance as vector. This is the second report of D. immitis development in A. albopictus from Brazil. The present data reinforce the role of this species as vector of D. immitis in an area where greater importance has long been given to A. aegypti.