Development of an autodissemination station for control of mosquito vectors

Banfield, Michael; Wang, Yi

Abstract

Autodissemination is a novel technique for insect control whereby target insects spread insecticide to their own habitats through their innate behaviors: a small treatment area results in far wider and target-specific coverage. This concept shows high potential for improved control of urban container-breeding mosquitoes, many of which vector deadly or debilitating diseases, such as dengue, Chikungunya and yellow fever, and also hamper outdoor activity through incessant biting behaviors. These peridomestic mosquitoes are problematic to manage with the aerial spray and fogging regimes typically used by vector control. As container-breeding mosquitoes continue to expand their distribution, dengue and other mosquito-borne pathogens have risen globally. It is imperative that new tools be explored to suppress vector populations and mitigate disease transmission at a landscape level. This project evaluates the feasibility of using autodissemination in a novel device for operational mosquito control against both Aedes albopictus and Aedes aegypti. Prototype autodissemination devices, or """"""""stations,"""""""" will be conceived, designed and evaluated for control of Ae. aegypti and Ae. albopictus, container-breeding vector species now infesting all non-Antarctic continents. As they seek small containers in which to lay their eggs, gravid female mosquitoes will visit the stations and pick up a powdered material containing an insect growth regulator (IGR). Insect growth regulators specifically target the hormonal pathways critical to insect development and are essentially non-toxic to vertebrates. The target mosquito species exhibit what is known as """"""""skip oviposition,"""""""" meaning that they deposit eggs from a single clutch in multiple containers. That """"""""skipping"""""""" behavior increases the likelihood that females visiting the station will subsequently visit other breeding sites, such as tree holes or buckets, and inoculate the water in those areas with tiny, but lethal doses of the IGR. All immature mosquitoes in those treated sites will not become viable adults capable of vectoring disease. To maximize field efficacy and minimize the labor and costs involved in use, features of the ideal final design will include: zero maintenance once deployed;low cost;full biodegradability;high attraction to the target mosquitoes;extended water retention and attraction through dry periods;high toxicant loading on visiting mosquitoes;and low environmental risk. Prototype stations and IGR formulations will be tested against live mosquitoes to optimize attractancy, water retention, field durability, extended efficacy, and transfer to and from mosquitoes. High potential candidate designs will be evaluated in small cage (1m3) bioassays to validate transfer between the station and other breeding containers via the mosquitoes. Autodissemination from the final prototype will be tested in replicated room (35m3) bioassays. The final prototype will be suitable for large- scale field testing in Phase II in a cooperative project with the Rutgers Center for Vector Biology

Public Health Relevance

The proposed research will evaluate a simple, low-cost device with high potential to control populations of container-breeding mosquitoes worldwide, thereby lessening a global disease threat and outdoor nuisance. This device will provide a novel and highly-effective means to target the primary vectors of dengue fever, Chikungunya and West Nile virus and be suitable for cost-effective use around the globe with minimal risk to human beings, non-target animals or the surrounding environment.