Mysore Keshava, Oxley James D, Duckham Craig, Castilla-Gutierrez Clarissa, Stewart Akilah T M, Winter Nikhella, Feng Rachel Shui, Singh Satish, James Lester D, Mohammed Azad, Severson David W, Duman-Scheel Molly
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA.
Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN, USA.
Sci Rep. 2024 Dec 4;14(1):30186. doi: 10.1038/s41598-024-81800-5.
Large household water storage containers are among the most productive habitats for Aedes aegypti (Linnaeus, 1762), the primary mosquito vector for dengue and other arboviral pathogens. Increasing concerns for insecticide resistance and larvicide safety are limiting the successful treatment of large household water storage containers, which are among the most productive habitats for Aedes juveniles. The recent development of species-specific RNAi-based yeast larvicides could help overcome these problems, particularly if shelf stable ready-to-use formulations with significant residual activity in water can be developed. Here we examine the hypothesis that development of a shelf-stable controlled-release RNAi yeast formulation can facilitate lasting control of A. aegypti juveniles in large water storage containers. In this study, a dried inactivated yeast was incorporated into a biodegradable matrix containing a mixture of polylactic acid, a preservative, and UV protectants. The formulation was prepared using food-grade level components to prevent toxicity to humans or other organisms. Both floating and sinking versions of the tablets were prepared for treatment of various sized water containers, including household water storage tank-sized containers. The tablets passed accelerated storage tests of shelf life stability and demonstrated up to six months residual activity in water. The yeast performed well in both small and large containers, including water barrels containing 20-1000 larvae each, and in outdoor barrel trials. Future studies will include the evaluation of the yeast larvicide in larger operational field trials that will further assess the potential for incorporating this new technology into integrated mosquito control programs worldwide.
大型家用储水容器是埃及伊蚊（林奈，1762年）最适宜繁殖的栖息地之一，埃及伊蚊是登革热和其他虫媒病毒病原体的主要蚊虫传播媒介。对杀虫剂抗性和杀幼虫剂安全性的日益关注，限制了对大型家用储水容器的有效处理，而大型家用储水容器是埃及伊蚊幼虫最适宜繁殖的栖息地之一。基于物种特异性RNAi的酵母杀幼虫剂的最新进展可能有助于克服这些问题，特别是如果能开发出在水中具有显著残留活性的货架稳定即用型制剂。在此，我们检验了一个假设，即开发一种货架稳定的控释RNAi酵母制剂可以促进对大型储水容器中埃及伊蚊幼虫的持久控制。在本研究中，将干燥的灭活酵母掺入含有聚乳酸、一种防腐剂和紫外线防护剂混合物的可生物降解基质中。该制剂使用食品级成分制备，以防止对人类或其他生物产生毒性。制备了漂浮型和下沉型片剂，用于处理各种尺寸的水容器，包括家用储水箱尺寸的容器。这些片剂通过了保质期稳定性的加速储存测试，并在水中表现出长达六个月的残留活性。该酵母在小型和大型容器中均表现良好，包括每个装有20 - 1000只幼虫的水桶，以及在户外水桶试验中。未来的研究将包括在更大规模的实际田间试验中评估酵母杀幼虫剂，这将进一步评估将这项新技术纳入全球综合蚊虫控制计划的潜力。
