A LARGE-SCALE FIELD TRIAL WITH DICHLORVOS AS A RESIDUAL FUMIGANT INSECTICIDE IN NORTHERN NIGERIA

Abstract

An extended field trial with dichlorvos was carried out in the Kankiya District of Northern Nigeria during 1963. Two types of dispenser were used-the dichlorvos-impregnated-montan-wax type and the liquid-dichlorvos type. The objective of the trial was to see if dichlorvos would interrupt the transmission of malaria under local conditions when used at a dosage of one dispenser per 15 m(3) of living space. On the basis of epidemiological findings-both parasitological and entomological-it was found that, owing to excessive ventilation in the huts treated, an adequate concentration of dichlorvos was not maintained, and transmission continued uninterrupted.