However, RVF virus also exists in most countries of sub-Saharan Africa and Madagascar. In September 2000, RVF was for the first time reported outside of the African Continent. Cases were confirmed in Saudi Arabia and Yemen in the Arabian Peninsula. A wide variety of mosquito species may act as the vector for transmission of RVF virus. Aedes mosquitoes may acquire the virus from feeding on infected animals.
Mosquito eggs can survive for years in dry conditions and hatch during rainfall.
Domestic animals like sheep, cattle, camels and goats can be infected. Uninfected mosquitoes can acquire the virus from these infected animals and amplify it by transmitting it to other uninfected animals. Sheep are more susceptible to RVF compared to cattle and goats. An epizootic of RVF may first manifest as a wave of unexplained abortions among livestock. Specimens should be sent in plain tubes to the Virology laboratory at Singapore General Hospital.