A promising technology, the RNA interference (RNAi) pathway is active in most eukaryotic cells and has evolved to silence gene expression with high specificity by the production of small interfering RNAs (siRNAs) of short length (21–25 bp) 29. There is a critical need to develop biofriendly pesticides that can easily be integrated into lethal ovitrap control programs.
Large volume lethal ovitraps, while effective in reducing mosquito populations, face challenges relative to insecticide resistance as well as adverse effects on non-target organisms. These larger volume traps have been shown to out-compete smaller volume lethal ovitrap designs 26. Both traps utilize a hay infusion for enhanced attraction of gravid females. The AGO has a 19 L volume and contains 10 L of water, with lethality provided by a sticky surface adhesive 28. The GAT has a 10 L volume and contains 3 L of water, with lethality typically provided by an insecticide surface spray 27. The two most advanced lethal ovitraps are the Gravid Aedes Trap (GAT) and the Aedes Gravid Ovitrap (AGO). More recently, concerted efforts have been directed at developing lethal ovitraps that: (1) are larger volume, (2) often spiked with attractants to lure gravid females, and (3) may include physical mechanisms like sticky boards to capture females that enter the traps 26. Ovitraps consisting of small containers (usually ~ 500 ml) with water and an oviposition substrate have been employed as Aedes surveillance tools for decades 23, 24, 25. Still, uncovered water storage drums and tanks are often the most prolific sources of Aedes mosquitoes in neighborhoods 14, 19, 20, 21, 22. Gravid Aedes females are known to practice ‘skip oviposition’, wherein they prefer to distribute eggs across multiple containers if given a choice, thereby maximizing the numbers of larval positive containers that mosquito control programs need to target 18, 19. The unreliability of piped water services in these areas, encourages active water storage in drums and tanks, as well as discarded container availability around houses, which combine to facilitate mosquito breeding 16, 17. Gravid Aedes females actively seek to oviposit in man-made containers in and around human dwellings 13, 14, with a majority of mosquito breeding often seen in neighborhoods with low and medium socioeconomic levels 15. Therefore, a range of alternative methods that target larval or adult stages are being developed and tested 11, 12. Notably resistance to all commonly used chemical insecticides is widespread among Aedes populations, thus limiting their effectiveness 10. Disease prevention or reduction, globally, of these arboviruses has historically depended on efforts directed at controlling the mosquito vectors, most often by breeding site reduction and insecticide applications 9. Efforts to prevent transmission or provide treatment for these arbovirus diseases by development of effective vaccines or antiviral drugs remain largely ineffective 5, 6, 7, 8.
This severely limited our intent to saturate these areas with ovitraps, indicating that future studies must include plans to account for these inaccessible zones during trap placement.Īedes aegypti (L.) and to a lesser extent Aedes albopictus (Skuse) are the primary global mosquito vectors of multiple arboviruses, such as dengue, chikungunya, Zika, and yellow fever that significantly impact human health 1, 2, 3, 4. Although yeast-baited ovitraps were highly attractive to gravid Aedes females, a primary limitation encountered within the Treatment sites was the inability to gain access to residential compounds for trap placement, primarily due to residents being absent during the day. Our goal was to gain baseline information on efforts to saturate the Treatment sites with ovitraps within 20–25 m of each other and compare oviposition rates at these sites with background oviposition rates in Control and Vector Areas. 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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#Ivcd ministry of health trinidad trial
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. 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).
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