Evaluation of lambdacyhalothrin-impregnated bednets in a malaria endemic area of India. Part 2. Impact on malaria vectors.

In malaria endemic villages of the Indian State of Orissa, the impact of bednets treated with lambdacyhalothrin at 25 mg/m2 on malaria vectors was assessed during a 3-year intervention trial beginning in May 1990. The main malaria vector was Anopheles culicifacies with a small contribution from Anopheles fluviatilis. The impregnated bednets caused a significant reduction in vector density as assessed by morning indoor resting catches, man-biting rate, light trapping, the proportion of females engorged with human blood, and the parity rate as compared with villages with untreated or no nets. No statistically significant difference was observed in these parameters between the villages with untreated nets or no nets. The trial demonstrated that the lambdacyhalothrin-treated nets were highly effective against the malaria vectors.