Impact of a spatial repellent product on Anopheles and non-Anopheles mosquitoes in Sumba, Indonesia

• Published in: Malaria Journal
• Main Authors: Dendi H. Permana, Siti Zubaidah, Lepa Syahrani, Puji B. S. Asih, Din Syafruddin, Ismail E. Rozi, Anggi P. N. Hidayati, Sully Kosasih, Farahana K. Dewayanti, Nia Rachmawati, Rifqi Risandi, Michael J. Bangs, Claus Bøgh, Jenna R. Davidson, Allison L. Hendershot, Timothy A. Burton, John P. Grieco, Evercita C. Eugenio, Fang Liu, Nicole L. Achee, Neil F. Lobo
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: Spatial repellent; Anthropophagic; Anopheles; Mosquitoes; Sumba; Indonesia; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-022-04185-8; https://doaj.org/article/52af96d7eac447d994c19e93cdd2ecee

Abstract Background The East Nusa Tenggara province, Indonesia, contributed to 5% of malaria cases nationally in 2020, with other mosquito-borne diseases, such as dengue and filariasis also being endemic. Monitoring of spatial and temporal vector species compositions and bionomic traits is an efficient method for generating evidence towards intervention strategy optimization and meeting disease elimination goals. Methods The impact of a spatial repellent (SR) on human biting mosquitoes was evaluated as part of a parent cluster-randomized, double-blinded, placebo-controlled trial, in Sumba, East Nusa Tenggara. A 10-month (June 2015–March 2016) baseline study was followed by a 24-month intervention period (April 2016 to April 2018)—where half the clusters were randomly assigned either a passive transfluthrin emanator or a placebo control. Results Human-landing mosquito catches documented a reduction in landing rates related to the SR. Overall, there was a 16.4% reduction (21% indoors, and 11.3% outdoors) in human biting rates (HBR) for Anopheles. For Aedes, there was a 44.3% HBR reduction indoors and a 35.6% reduction outdoors. This reduction was 38.3% indoors and 39.1% outdoors for Armigeres, and 36.0% indoors and 32.3% outdoors for Culex species. Intervention impacts on the HBRs were not significant and are attributed to large inter-household and inter cluster variation. Anopheles flavirostris, Anopheles balabacensis and Anopheles maculatus individually impacted the overall malaria infections hazard rate with statistically significance. Though there was SR-based protection against malaria for all Anopheles species (except Anopheles sundaicus), only five (Anopheles aconitus, Anopheles kochi, Anopheles tessellatus, An. maculatus and An. sundaicus) demonstrated statistical significance. The SR numerically reduced Anopheles parity rates indoors and outdoors when compared to the placebo. Conclusion Evidence demonstrating that Anopheles vectors bite both indoors and outdoors indicates that currently implemented ...