Impact of etofenprox (Vectron 20 WP) indoor residual spray on malaria transmission.

BACKGROUND & OBJECTIVE A longitudinal study was carried out to assess the impact of indoor residual spray with Vectron 20 WP (etofenprox) against Anopheles culicifacies and on malaria transmission in a selected village of Dadri primary health centre (PHC), District Gautam Budh Nagar, Uttar Pradesh, India. METHODS Two villages, namely Patadi and Anandpur in District Gautam Budh Nagar, Uttar Pradesh, with similar malaria incidence and vector prevalence were selected for the present evaluation. In one village two rounds of indoor spraying of etofenprox (0.1 g/m(2)) were done at an interval of 12 wk and the other village was kept as control where no intervention except intensive active surveillance for early detection and prompt treatment (EDPT) was undertaken during the study period. Entomological and epidemiological data were collected using standard procedures. RESULTS Persistence of the effectiveness of etofenprox against An. culicifacies was observed up to 12 wk. Spraying of etofenprox significantly reduced the density (P<0.001) and proportion of parous An. culicifacies mosquitoes (P<0.05) in the experimental village. There was a significant reduction in malaria cases in the experimental village during the post-spray period when compared to the control village (P<0.05). No adverse effect was reported by the spraymen and inhabitants during and after the spray. INTERPRETATION & CONCLUSION Indoor residual spray of etofenprox (0.1 g/m(2)) with an interval of three months in between two rounds of spray produced the desired impact in reducing the indoor resting density of vector mosquitoes and also in curtailing malaria transmission in the sprayed village when compared with the control village without spray.