Review the role of transovarial transmission by mosquitoes and wildlife circulation in the persistence of Rift Valley fever virus

Abstract

Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic viral disease affecting domestic and wild animals as well as humans, primarily in Africa and the Arabian Peninsula, with a proven ability to emerge in new geographic areas. Despite its importance, the mechanisms for maintaining RVFV between epidemics remain unclear. This review highlights the vertical transmission of the virus in mosquitoes, the role of wildlife as a reservoir host and the impact of climate change on disease outbreaks. Field and laboratory studies show that RVFV is primarily maintained by transovarial virus transmission in mosquitoes, while wildlife, particularly ruminants, acts as a reservoir during inter-epidemic periods. Climate change promotes outbreaks by increasing populations of RVFV vectors, particularly Aedes mosquitoes, in areas where heavy precipitation, flooding and high temperatures provide conditions for infected mosquitoes to multiply