An epidemiological assessment of the residual effect of DDT on Anopheles hyrcanus sensulato and A. pulcherrimus (Theobold) in the North eastern region of Afghanistan.

In the irrigated zones of North-eastern region of Afghanistan malaria transmission is sustained by A. pulcherrimus and A. hyrcanus despite many years of DDT spraying. A. hyrcanus is an exophilic and exophagic mosquito, strongly resistant to DDT. A. pulcherrimus is still largely susceptible to the insecticide but seems to be deterred from entering houses when these are sprayed with DDT. Entomological and parasitological studies in an area of the province of Kunduz where DDT has not been applied for 2 consecutive years have clearly indicated that the insecticide still plays an important role in reducing malaria transmission in the area though, as expected, it cannot interrupt transmission. A deterioration of the epidemiological situation in the area can be expected if the insecticide is withdrawn. The technical problems now existing in the irrigated zones of the North-eastern region of Afghanistan cannot be solved by routine attack measures. Malaria in the area can be eradicated only with the introduction of new attack measures which are very expensive and for which, at present, the necessary funds are not available.