Transmission electron micrograph (TEM) of tissue that had been infected with Rift Valley fever (RVF) virus. RVF virus is a member of the genus Phlebovirus in the family Bunyaviridae and was first reported in livestock in Kenya around 1900. It is found to be an acute, fever-causing viral disease that affects domestic animals (such as cattle, buffalo, sheep, goats, and camels) and humans. RVF is most commonly associated with mosquito-borne epidemics during years of unusually heavy rainfall. Humans can get RVF as a result of bites from mosquitoes and possibly other bloodsucking insects that serve as vectors. Humans can also get the disease if they are exposed to either the blood or other body fluids of infected animals.