Natural infections of Dirofilaria immitis in Aedes (Stegomyia) polynesiensis and Aedes (Finlaya) samoanus and their implication in human health in Samoa.

Dirofilaria immitis infections were observed in Aedes polynesiensis and Ae. samoanus in Samoa, together with Wuchereria bancrofti infections, in a study on sub-periodic bancroftian filariasis during 1978-1980. In the 4 indicator villages, the infection rate in Ae. polynesiensis was 0.46% and the infective rate 0.09% (15,223 mosquitoes were dissected). The infection rate in Ae. samoanus was 0.20% and the infective rate 0.08% (10,089 dissected). In 45 selected villages throughout the country, Ae. polynesiensis infection and infective rates were 0.92% and 0.29% (7575 dissected) and the rates for Ae. samoanus were 0.21% and 0.07% (9093 dissected). Infection with D. immitis was comparable in degree and distribution to that with W. bancrofti. There was a steady and consistent exchange of parasites between the human and canine populations, creating conditions favourable for human dirofilariasis in Samoa. Clinicians are warned against this probable human infection.