Location: Mosquito and Fly Research Unit
Title: Evaluation of ULV applications against Old World sand fly (Diptera: Psychodidae) species in equatorial Kenya Authors
|Walker, Todd -|
|Farooq, Muhammad -|
|Gordon, Scott -|
|Clark, Jeffrey -|
|Ngere, Francis -|
|N'Gonga, Daniel -|
|Chepchieng, Clifford -|
Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2011
Publication Date: November 1, 2011
Repository URL: http://dx.doi.org/10.1603/ME11025
Citation: Britch, S.C., Linthicum, K., Walker, T.W., Farooq, M., Gordon, S.W., Clark, J.W., Ngere, F., N'Gonga, D., Chepchieng, C. 2011. Evaluation of ULV applications against Old World sand fly (Diptera: Psychodidae) species in equatorial Kenya. Journal of Medical Entomology. 48(6):1145-1159. Interpretive Summary: In this report we describe research designed to evaluate the performance of pest management equipment, chemicals, and techniques in a hot-arid environment. Current US military operations in harsh desert regions expose personnel to insects such as mosquitoes and sand flies. Sand flies pose a particular threat because of their ability to vector Leishmania parasites to humans, which can cause permanent disfiguring skin lesions or extremely serious permanent organ damage. The current pest management equipment and insecticide chemicals listed by the Department of Defense (DoD) have not been adequately tested in hot arid areas against sand flies. Additionally, new pesticide chemicals not yet listed by the DoD need to be evaluated for use in desert areas against sand flies. In this study, the first of its kind, we tested two types of pesticide sprayers and two pesticides to cause mortality in wild and colony reared sand flies in equatorial Kenya as a proxy for similar sand fly species and similar environments found in Iraq and Afghanistan. We found that in the hot arid environment, current DoD equipment and one pesticide performed well against sand flies and we determined that a new pesticide not yet listed by the DoD also performed well against sand flies and should be evaluated further.
Technical Abstract: Reducing populations of phlebotomine sand flies in areas prevalent for human leishmaniases is of ongoing importance to US military operations and civilian populations in endemic regions. Collateral reduction of sand flies or human cases of leishmaniases during pesticide campaigns against vectors of malaria indicate that residuals like DDT can be effective. However, not enough is known regarding the efficacy of the current arsenal of Department of Defense-approved pesticides. We need to know more about the potential for ultra-low volume ULV pesticide applications to control Old World sand fly vectors. In this study we examine the performance of 2 pieces of spray equipment, the Terminator ULV and the Grizzly ULV, with Duet and Fyfanon in four combinations against caged Phlebotomus duboscqi (Neveu-Lemaire) and wild populations of Phlebotomus species in a natural environment in western Kenya. All equipment and Fyfanon are approved and listed by the Armed Forces Pest Management Board, and both pesticides registered with the US Environmental Protection Agency. Caged sand flies were reared from local P. duboscqi and the area has long been studied as a human cutaneous and visceral Leishmania focus. Patterns of mortality across grids of sentinel sand flies showed greater efficacy from the Grizzly ULV sprayer regardless of chemical. Sand fly trapping of wild populations before and after treatments suggests local population suppression from ULV sprays. We discuss the implications of these findings for future military preventive medicine activities and encourage further investigations into the merits of ULV for enhancement of force health protection.