ARS | Publication request: Insecticide Treated Camouflage Sceening Reduces Sand Fly Numbers in Leishmania-Endemic Regions in Kenya

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 22, 2009
Publication Date: November 18, 2009
Citation: Linthicum, K., Britch, S.C., Wynn, W.W., Clark, J.W., Ng'Nonga, D., Ngere, F., Kibet, C., Walker, T.W., Farooq, M., Robinson, C.A., Smith, V.L., Dunford, J.C., Anyamba, A. 2009. Insecticide Treated Camouflage Sceening Reduces Sand Fly Numbers in Leishmania-Endemic Regions in Kenya [abstract]. The American Journal of Tropical Medicine and Hygiene. 81(5):165.

Technical Abstract: Current U.S. military operations in deserts face persistent threats from sand flies that transmit human Leishmania. In this study we investigated the efficacy of artificial barriers treated with residual insecticide to potentially reduce the risk of human infection from leishmaniasis by reducing the number of sand fly vectors. Bifenthrin treated and un-treated camouflage netting was used to construct open-topped 10 x 10 feet enclosures 6 feet high at a field station in Marigat, Kenya where sand flies which readily transmit Leishmania are prevalent. Eight foot eucalyptus wood poles were used as the frame for the enclosures. Light traps baited with carbon dioxide were used as surrogates for human hosts and were operated overnight from 1530-0700 h on selected dates. We estimated sand fly mortality in 4 treated and 4 non-treated enclosures at various days post-treatment during hot-dry and hot-heavy rainfall conditions in Marigat, Kenya by calculating the percent reduction in sand fly catch in treated enclosures as compared to untreated enclosures, a measure of relative efficacy of the treatment. We found a reduction in sand flies in treated enclosures when compared to untreated enclosures. Additionally, the difference in percentage found dead suggests that the toxic barrier is associated with a higher proportion of sand flies that die after being trapped, as compared to untreated enclosures. Phlebotomus duboscqi,Phlebotomus martini, and Sergentomyia schwetzi are thought to be the predominate sand fly species collected within the enclosures but identifications are pending. These results suggest that treated artificial barriers may be an effective tool to reduce Leishmania exposure to troops deployed in sand fly endemic regions, when used in conjunction with personal protective measures and other standard insect control measures.