Rift Valley Fever

About Rift Valley Fever

Rift Valley Fever RVF is a viral zoonosis that primarily affects animals but can infect humans. The virus was first identified in 1931 during an investigation of a sheep disease outbreak in the Rift Valley of Kenya. RVF is transmitted by mosquitoes, with Aedes and Culex species as primary vectors. Heavy rainfall and flooding trigger outbreaks by expanding mosquito breeding sites. Among animals, RVF causes high mortality in young animals and abortion storms in pregnant livestock. Human infections usually occur through contact with infected animal tissue or blood. Most human cases are mild, but a small percentage of patients develop severe forms including hemorrhagic fever, encephalitis, and retinitis. RVF has spread beyond Africa, with outbreaks in Saudi Arabia and Yemen in 2000. A veterinary RVF vaccine exists, and human vaccine candidates have been developed. Climate change may expand the geographic range of RVF.