Impact of residual spraying of Reldan against Anopheles culicifacies in selected villages of District Ghaziabad (Uttar pradesh), India

BACKGROUND & OBJECTIVES: Indoor residual spraying of Reldan 40% EC @ 0.5 and 1 g/m2 was done in Tatarpur and Chauna villages, respectively in Dhaulana PHC, Distt. Ghaziabad (U.P.) to evaluate its impact against Anopheles culicifacies and malaria incidence. Results were compared with that of Piyawali village which was taken as control area. METHODS: Four rounds of spray were done from 1999--2000 in human dwellings and cattlesheds in experimental villages. Entomological parameters--man hour density, parity rate, sporozoite rate, etc. were monitored using standard procedures. Epidemiological indicators such as SPR, SFR, cases/000, Pf/000 were also calculated. Cone bioassays as per WHO method were also carried out to assess the persistence of the insecticide on different surfaces. RESULTS: Entomological results revealed that spraying of reldan @ 0.5 g/m2 resulted in significant reduction in adult densities of An. culicifacies in sprayed villages over the control village. Spraying also resulted in reduction of percent parous females, reduction in malaria incidence (p < 0.05). INTERPRETATION & CONCLUSION: Reldan showed high efficacy @ 0.5 g/m2 in controlling the densities of An. culicifacies and malaria incidence. However, double dosage of reldan @ 1 g/m2 can be used for comprehensive vector control provided > 95% spray coverage is achieved.