A randomized controlled trial of insecticide-treated bednets and chaddars or top sheets, and residual spraying of interior rooms for the prevention of cutaneous leishmaniasis in Kabul, Afghanistan

Anthroponotic cutaneous leishmaniasis (ACL) is a significant public health problem in many towns and cities of south central Asia and the Middle East, resulting in disfigurement and disability which warrants preventive action. A randomized controlled trial was conducted in 1997/98 amongst a non-immune study population of 3666 people in Kabul, Afghanistan, to compare the efficacy of insecticide-treated nets (ITNs), insecticide-treated Islamic cloth wraps (chaddars) used to sleep in, and residual pyrethroid spraying of individual houses for the prevention of ACL. Dosages of insecticide were: ITNs with permethrin, 0·5 g/m2; chaddars with permethrin, 1 g/m2; rooms with lambdacyhalothrin, 30 mg/m2. Cases of ACL were diagnosed on clinical criteria. At the end of the trial period (15 months) the incidence of ACL amongst controls was 7·2%, amongst ITN users 2·4% (OR 0·31, 95% CI 0·2-0·5), amongst impregnated chaddar users 2·5% (OR 0·33, 95% CI 0·2-0·6) and amongst residents of sprayed houses 4·4% (OR 0·60, 95% CI 0·3-0·95). ITNs and impregnated chaddars were equally effective, providing about 65% protective efficacy, with approximately 40% protective-efficacy attributable to individual house spraying. No significant differences for age or sex were found between new cases in the intervention and control groups. No serious side-effects were reported and interventions were generally popular; ITNs were the most popular, followed by residual spraying and then impregnated chaddars.