Publications by authors named "Lester D James"

Article Synopsis
  • Large household water storage containers are key breeding sites for Aedes aegypti mosquitoes, which spread diseases like dengue.
  • Concerns over insecticide resistance and safety are challenging effective mosquito control, leading researchers to explore RNAi-based yeast larvicides as a solution.
  • A study developed a shelf-stable, controlled-release yeast formulation that shows promise for lasting mosquito control, demonstrating effectiveness in various container sizes and remaining active for up to six months.
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Dengue and other arboviruses remain a global threat, and enhanced efforts to control the mosquitoes that transmit them are urgently needed. A survey of potential manmade (L.) and (Skuse) oviposition containers was performed in four communities near the end of the typical dry season in 2018 in Trinidad, West Indies.

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Article Synopsis
  • G protein-coupled receptors (GPCRs) are promising targets for insecticides, and RNA interference (RNAi) technology could allow the creation of safe pesticides that only affect specific pests like mosquitoes.
  • The study focused on developing a yeast strain, 5-HTR.426, that uses RNAi to silence a specific serotonin receptor gene in mosquitoes, which could kill them without harming beneficial non-target species.
  • Experimental results showed that consuming this yeast led to significant mortality in various mosquito species while causing neural defects, but it remained safe for other insects, indicating the potential for RNAi-based mosquito control in future applications.
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The use of lure-and-kill, large-volume ovitraps to control Aedes aegypti and Aedes albopictus populations has shown promise across multiple designs that target gravid females (adulticidal) or larvae post-oviposition (larvicidal). Here we report on a pilot trial to deploy 10 L yeast-baited ovitraps at select sites in Curepe, Trinidad, West Indies during July to December, 2019. Oviposition rates among ovitraps placed in three Treatment sites were compared to a limited number of traps placed in three Control areas (no Aedes management performed), and three Vector areas (subjected to standard Ministry of Health, Insect Vector Control efforts).

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Dengue, Zika, chikungunya and yellow fever viruses continue to be a major public health burden. Aedes mosquitoes, the primary vectors responsible for transmitting these viral pathogens, continue to flourish due to local challenges in vector control management. Yeast interfering RNA-baited larval lethal ovitraps are being developed as a novel biorational control tool for Aedes mosquitoes.

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RNA interference (RNAi), a technique used to investigate gene function in insects and other organisms, is attracting attention as a potential new technology for mosquito control. Saccharomyces cerevisiae (baker's yeast) was recently engineered to produce interfering RNA molecules that silence genes required for mosquito survival, but which do not correspond to genes in humans or other non-target organisms. The resulting yeast pesticides, which facilitate cost-effective production and delivery of interfering RNA to mosquito larvae that eat the yeast, effectively kill mosquitoes in laboratory and semi-field trials.

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