Kenneth J. Linthicum Seth C. Britch Wayne W. Wynn Ryan C. Grubbs

1. Insecticide treated camouflage screening reduces sand fly numbers in Leishmania-endemic regions in Kenya Jeffrey W. Clark Clifford KibetChepchieng Francis GareNgere VitaliceOmondiOpondo Daniel OtienoNg’onga Fredrick OchienaOoko Todd W. Walker James C. Dunford Muhammad Farooq Cathy A. Robinson Vincent L. Smith Kenneth J. Linthicum • Seth C. Britch Wayne W. Wynn Ryan C. Grubbs Assaf Anyamba We used bifenthrin-treated and un-treated current DoD-issue camouflage netting to construct 6 ft high open-topped 10 ft x 10 ft enclosures at a field station in Marigat, Kenya. Here, sand flies which readily transmit Leishmania are prevalent. Eight foot eucalyptus wood poles were used as the frame for the enclosures. 3 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. Light traps baited with CO2 were used as surrogates for human hosts and were operated overnight from 1530-0700 h on selected dates. OBJECTIVE 2 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; these reductions persisted for nearly two months. We also studied the longevity of the bifenthrin treatment by performing Culexquinquefasciatusmortality bioassays on samples of the treated and untreated netting cut on many of the same days trapping was carried out. The bifenthrin treatment was lethal to mosquitoes for over eight months on the camouflage screening. 5 4 CONCLUSIONS 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. Additionally, the difference in percentage of sand flies found dead (data not shown) suggests that the toxic barrier is associated with a higher proportion of sand flies that die after being trapped, as compared to untreated enclosures. http://www.ars.usda.gov/saa/cmave