Studies on bancroftian filariasis in Liberia, West Africa. V. The influence of treatment with diethylcarbamazine and vector control on the transmission of Wuchereria bancrofti.

The transmission intensity of bancroftian filariasis was investigated during a study on filariasis control carried out in eight villages of the savanna area in the hinterland of Liberia. Although the microfilarial reservoir had been reduced considerably in the human population of two villages by mass treatment with the filaricide drug diethylcarbamazine the transmission of Wuchereria bancrofti was continued without any distinct reduction. The transmission however decreased distinctly or was even interrupted when residual spraying with DDT was used in two other villages for vector control. The combined application of both control measures did not prevent completely that mosquitoes became infected with mature stages of W. bancrofti.