Risk factors for occurrence and abundance of Aedes aegypti and Aedes bromeliae at hotel compounds in Zanzibar

Abstract

BACKGROUND : A field survey was performed to investigate local environmental factors promoting occurrence and abundance of Aedes aegypti and Ae. bromeliae mosquitoes at hotel compounds in the south-east coastal region of Zanzibar Island. METHODS : The potential risk factors were determined using generalized linear mixed models. Aedes (Stegomyia) spp. indices such as container index (CI) and pupae per container (PPC) index were also estimated. RESULTS : Aedes aegypti and Ae. bromeliae were the most abundant vector species, accounting for 70.8% of all Aedes mosquitoes collected. The highest CI was observed for plastic containers irrespective of the season, whereas the highest PPC was observed for coconut shells and aluminium containers in the rainy and dry seasons, respectively. The risk of Aedes mosquito occurrence and abundance were significantly associated with presence of plastic containers, coconut shells, used tyres and steel containers. These were discarded in shaded places, in the open and gardens, or found in plant nurseries. CONCLUSION : This study shows that Aedes species of global health significance occur at hotel compounds on this part of Zanzibar Island. The occurrence and abundance are sustained by the presence of abundant and poorly managed solid wastes and containers used for gardening tasks. This highlights an urgent need for the adoption of area-wide environmentally sustainable Aedes mosquito management interventions that also integrate solid waste management and ornamental plant production practices for reducing the risk of arboviral disease epidemics.