Rift Valley fever (RVF) is one of the most serious transboundary animal diseases. It is a mosquito-borne viral disease, which causes periodic severe epidemics, principally involving ruminant animals (sheep, cattle and goats). RVF is also transmitted to humans causing a potentially fatal disease.

Until recently it had only been recognized in the African continent, but in 2000 it occurred in the Arabian Peninsula. Major epidemics have occurred at irregular intervals of 10-30 years in the eastern half of Africa, from South Africa to Egypt. As well as its severe socio-economic and public health consequences, it is a major constraint to international livestock trade.