Impact of Olyset nets on malaria transmission in India.

BACKGROUND & OBJECTIVES: Efficacy of Olyset nets, long-lasting insecticidal nets were tested from August 2003 to August 2006 against Anopheles culicifacies, the vector which transmits 60% of all malaria cases in rural India. METHODS: Three villages in District Gautam Budh Nagar (Uttar Pradesh), India were selected for the trial and Olyset nets were distributed in one village, in another village untreated nets were distributed and the third village was kept as control where nets were not used. Entomological, and epidemiological data were collected using standard methods. RESULTS: The use of Olyset nets reduced the indoor resting density of An. culicifacies and also reduced mosquito entry into the structures where Olyset nets were used. No mosquitoes were caught landing on the Olyset nets. There was a reduction in the parity rate of An. culicifacies in the Olyset net village as compared with untreated net and no net villages. The impact of Olyset nets was observed on malaria incidence and only one case of Plasmodiumfalciparum malaria was reported in the Olyset net village but these continued to be found in the village with untreated nets and the control. CONCLUSION: Results of the present study confirmed that Olyset nets are highly effective in reducing the indoor resting density of mosquitoes, man-vector contact and malaria incidence.