Indoor Residual Spraying With Fludora Fusion for Malaria Control in Pyrethroid-Resistant Areas of Gujarat, India: A Community-Randomized Trial.

Abstract

Background: The development of insecticide resistance in malaria vectors has necessitated a need to evaluate new insecticide molecules with different modes of action. In the present study, Fludora Fusion 562.5 WP-SB (clothianidin 50% + deltamethrin 6.25% AI/kg) was evaluated for its efficacy and residual action for the control of pyrethroid-resistant malaria vector, Anopheles culicifacies (Diptera: Culicidae), during May 2017 to February 2018 in Gujarat state, India. Methods: Fludora Fusion at the dose of 225 mg AI/m² and bendiocarb at a dose of 400 mg AI/m² as a positive control were sprayed in 5 villages each in districts of Kheda, Vadodara, and Panchmahal. The persistence of their efficacy on different local surfaces was determined against An. culicifacies. Entomological indices such as indoor resting density, human landing collections, pyrethrum spray collections, and exit trap collections were monitored to assess the impact of spraying. Results: The observed residual action of Fludora Fusion on mud and cement surfaces was for 6 months and bendiocarb for 3-4 months on both surfaces. Indoor resting densities and parous rate of An. culicifacies were significantly lower in houses sprayed with Fludora Fusion compared to bendiocarb-sprayed houses. Daily entomological inoculation rate (EIR) declined from 1.275 during prespray period to 0.5225 in the Fludora Fusion arm and 0.3802 in the Ficam arm in postspray period, indicating a reduction in the malaria transmission potential of An. culicifacies in both arms. Conclusion: Based on the residual action of the Fludora Fusion on most common sprayed surfaces and its effects on the elements of vectorial capacity, Fludora Fusion at 225 mg/m² dose was found effective for more than 6 months and could be a potential option for the control of resistant mosquito vectors.