Rift Valley fever zoonotic disease was first identified in 1931 during an outbreak investigation among sheep on a farm in Kenya’s Great Rift Valley. Since its discovery in 1931, RVF outbreaks have been observed across sub-Saharan Africa and, more recently, in the Middle East. The discovery of the RVF virus marked a significant milestone in understanding the complex relationship between animal health and human infections. This mosquito-borne illness belongs to the genus Phlebovirus within the family Bunyaviridae, which also includes other notable viruses such as yellow fever.
In eastern Africa, particularly East Africa and parts of the African continent where Culex mosquitoes are prevalent, RVF has become endemic due to favorable environmental conditions for its spread. These include heavy rainfall periods that lead to increased mosquito populations acting as vectors for transmitting the virus from infected animals to susceptible hosts like cattle, sheep, goats, camels, buffalo, and antelope species, as well as rodents like rats and mice.
- 1931: First identification of RVF during an epidemic among sheep in Kenya’s Great Rift Valley
- Late 20th century: Outbreaks reported across sub-Saharan Africa
- 2000 – present: Cases documented outside Africa; notably Saudi Arabia and Yemen
The history of Rift Valley Fever has been well documented and is an important part of understanding the virus.