Efficacy Of 10% Emulsifiable Concentrate (Ec) Of Sypertix® For Tsetse Fly Control In Kiboko Makueni County, Kenya.

Abstract

Controlling tsetse flies remain an integral part of trypanosomiasis management. Pour on insecticides have been used in controlling tsetse flies in cattle. Efficacy studies of various pyrethroid insecticides have shown to control tsetse flies. In this study, the feeding success, knockdown effect and efficacy of 10%EC Sypertix®, a pyrethroid insecticide, was assessed on laboratory reared male Glossina pallidipes in dry and wet seasons in three study sites namely: Mulili, Kaasuvi and Kiboko in Makueni County, Kenya. Three groups of cattle each comprising of six cows were selected from each study site. A geigy cage holding 30 tsetse flies was strapped at the flank of each cow in each group for ten minutes during the bioassay. The feeding success was ascribed as fed or unfed after the ten minutes of exposure. The knockdown rates were observed at 0, 5, 10 and 20 minutes, after the ten minutes of exposure. Mortality rates were observed after 24 hours post treatment on the experimental cattle. The feeding success of tsetse flies increased with significant variations from week zero to the third week in the treated groups (Sypertix® and Domenix®), while there were no significant variations in the fourth week in both the dry and wet seasons (P=0.05). There was a significant difference in feeding success from week 0 to week 3 between the treated groups and the control group. There was a 90% knockdown in the insecticide treated groups which occurred 5 minutes post treatment up to the second week in both dry and wet seasons. A higher number of knockdown in tsetse flies, which declined with increase in time, was observed in treated cattle. There was however, significant variation between knockdown observed in treated groups (Sypertix® and Domenix®) compared to the control (untreated) group. A cut off mortality of 80% within 24th hours occurred two weeks post exposure for the insecticide treated groups (Sypertix® and Domenix®) in both dry and wet seasons. Mortalities obtained were comparable and had no significant variation (P=0.05) between the treated groups (Sypertix® and Domenix®) but varied significantly from the control (untreated) group. xiv The study confirms that Sypertix® is efficacious in both seasons and its persistence in the wet season during the wash off by rains, is a novel quality that shows it can be used as an alternative Alphacypermethrin for control of tsetse flies. The insecticide should therefore be reapplied on the cattle after two weeks of initial application to maintain its efficacy. The findings of this study show the potential of Sypertix® in decreasing the re-invasion of tsetse flies and prevalence of trypanosomiasis.