Epidemiology of bancroftian filariasis in Nagate and Abumize villages, Nagasaki Prefecture, especially in relation to vector mosquitoes. 4. Filariasis eradication experiment by the control of vector mosquitoes.

In Nagate Village where bancroftian microfilarial incidence in 1961 had been 14,0%, control works for the major vector, Culexpipienspallens, have been carried out. Since 1962 residual spraying was made once a year usually on mid-June prior to the breeding out of the vector mosquito and larvicide applications were continued once a week throughout the breeding season. By the end of 1965 nearly half of initial carriers became negative and clear decreasein microfilarial count was found. From the reductions by the present time in the microfilarial incidence and count an expectation for future diminution of filariasis was made.