Distribution and abundance of key vectors of Rift Valley fever and other arboviruses in two ecologically distinct counties in Kenya

Abstract

Rift Valley fever (RVF) causes outbreaks in Africa and the Arabian Peninsula with significant public health and economic consequences, and can be transmitted to humans through mosquito bites and contact with infected livestock. Rift Valley fever is a mosquito-borne disease caused by the Rift Valley fever virus (RVFV) transmitted by diverse species of mosquitoes broadly classified into primary and secondary vectors. Primary vectors consist of floodwater Aedes (which maintain the virus in their drought-resistant eggs that hatch following heavy persistent rains with flooding, after which the emerging infected adult female mosquitoes initiate transmission to nearby animals) Secondary vectors, mainly Culex and potentially Anopheles and Mansonia species (which take over the breeding sites of the Aedes mosquitoes and transmit RVFV). The study presents the geographical distribution and abundance of viruses transmitted by the mosquitoes in 2 Kenyan counties—Isiolo (medium risk) and Tana-River (high risk)—which may assist with risk assessment for mosquito-borne diseases. This is output from the ‘Prediction and Preparedness against Outbreaks with Devastating Economic Impact’ project. It was partly funded by the UK Department for International Development, a core donor of the International Centre of Insect Physiology and Ecology