Location: Mosquito and Fly Research Unit
Title: Advances in the discovery of novel repellents and application strategies Author
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 24, 2010
Publication Date: N/A
Technical Abstract: The United States Department of Agriculture’s (USDA) Insects Affecting Man and Animals Research Laboratory in Orlando, Florida received its first sample insecticide, a natural pyrethrin mixture, in 1942. In 1963, this laboratory moved to Gainesville, Florida, where it now resides at the Center for Medical, Agricultural, and Veterinary Entomology (CMAVE). During the nearly 70 years, over 30,000 repellent and insecticide products have been evaluated, including N,N-diethyl-3-methylbenzamide (DEET), permethrin-treated military uniforms, and ultra-low volume (ULV) insecticide approaches. The present day emphasis of the Mosquito and Fly Research Unit at the CMAVE is to conduct research on medically-important biting and filth flies. The unit has a history of exploring host odors and this research has led to the identification of attractants and attractant blends. It also led to the discovery of a class of compounds that impart a spatial effect leading to inability of the insect to detect host odors. In laboratory bioassays, these compounds inhibit the attraction of Aedes aegypti and Anopheles albimanus mosquitoes and Phlebotomus papatasi sand flies to a normally attractive stimulus (e.g., human odors). Exploration of subsets of the over 30,000 chemical structures tested by the USDA has led to the discovery of new topical repellents. A total of 68 piperidine and carboxamide candidate mosquito repellents have been evaluated for duration of repellency and minimum effective dosage for repellency using a cloth patch assay. Several of these compounds have shown repellent efficacy comparable to or greater than that of DEET. Current studies are being extended to evaluate these repellents against other arthropod species, including stable flies (Stomoxys calcitrans) and ticks (Ixodes and Ambylomma). The United States Army and United States Marine Corps (USMC) are using insecticide-treated uniforms that incorporate fire resistant materials. Because of changes in the uniform’s fabric composition and construction, the permethrin is absorbed and retained less effectively. Therefore, the USMC now provides only factory-treated uniforms to its personnel. The Army uniform is a greater challenge due to its construction, which leads to lowered efficacy when treated with appropriate levels of permethrin. Novel uniform impregnates and combinations are being explored. Compared to permethrin alone, these systems provide the wearer with increased protection from mosquito and sand fly bites. Other aspects of the USDA-ARS program will be discussed in presentations by Dr. Gary Clark and Dr. Kenneth Linthicum.