OVIPOSITION PREFERENCE OF Aedes aegypti MOSQUITOES IN MSAMBWENI SUB-COUNTY, KWALE COUNTY, KENYA

Abstract

Aedes aegypti is the primary vector of dengue fever virus (DENV) worldwide. Kenya has reported increased outbreaks of dengue fever along its coast region in the last decade, with a corresponding increase in abundance of Ae. Aegypti. Infusions made from organic materials have been shown to act as oviposition attractants for Ae. Aegypti, however, studies on locally suitable infusion materials are lacking. The current study assessed the suitability of four locally available materials as oviposition infusions for use in control of Aedes aegypti in sub-county, Kwale County, Kenya. A secondary objective of the study Msambweni was to identify Ae. aegypti preferred oviposition microhabitats. Oviposition infusion preferences of four infusions made from leaves of banana, grass, neem, and coconut were assessed in laboratory, semi-field and field conditions. Ovitrapping in wall, grass, bush and banana microhabitats was done in 10 houses, each in urban (Ukunda) and rural (Msambweni) households to determine suitable oviposition microhabitats. Descriptive analyses were used to compare ovipositional responses among the different infusions and microhabitats. Overall, the highest (P<0.0001) oviposition responses were observed from banana infusion followed by neem (P<0.0001) and grass infusions (P<0.0001). Oviposition responses in neem and grass infusion were comparable. Coconut infusion resulted in the least oviposition response. Although female Ae. aegypti did not show preference to any microhabitat, the oviposition activity across all the microhabitats were highly enhanced by use of the organic infusions. However, the mean number of eggs laid in banana and bush microhabitats were higher (42.61±2.05 and 35.87±1.71respectively) compared to grass (32.55±1.66) and wall microhabitats (31.05±1.66). Banana leaves, mixed grass and neem tree leaves are suitable materials for oviposition infusions. Using these infusions, gravid mosquito could be attracted to oviposition sites that are laced with an insecticide to kill the eggs. Additionally, the small pockets of banana plantings should be important targets for integrated vector control programs.