Malaria control using permethrin applied to tents of nomadic Afghan refugees in northern Pakistan.

ABSTRACT

PIP: During 1989-90, in the North-West Frontier Province of Pakistan, a pilot study was conducted in the remote and politically unstable area of South Waziristan Agency (altitude, 1300-1750 m) to determine the feasibility of spraying about 5600 tents (used by more than 26,000 nomadic Afghan refugees) with permethrin and its effect on malaria prevalence. The researchers compared baseline data on the refugees and data from Pakistani schoolchildren with follow-up data on the nomadic Afghan refugees. The mosquito species harboring malaria parasites in the area were Anopheles culicifacies and A. stephensi. An effective permethrin residue persisted for at least 6 months after spraying. Between seasons, the prevalence of Plasmodium falciparum increased at a significantly lower rate among the Afghan nomads (6.4-15.3%) than the resident Pakistan population (3.2-45.6%). Prevalence decreased significantly among nomadic Afghan children after the permethrin intervention (46.9-16.3%; p 0.002). On the other hand, it increased significantly among the local Pakistani children (11.6-40.7%; p 0.001). There were no reports of adverse effects from permethrin spraying operations. The absence of toxic effects, the immediate impact on flies, and the lack of smell or color of the permethrin emulsion made the spraying operation acceptable among the nomads. These findings suggest that spraying tents with permethrin was a safe and culturally acceptable intervention.