ABSTRACT

Rift Valley Fever (RVF) was first recognized as a zoonotic disease in the 1930's in eastern Africa and has been observed since the 1950's in southern Africa. RVF entered Egypt like a storm in 1977 and killed over two million head of livestock and almost a thousand Egyptians and threatened Israel and the entire region. Egypt's domestic production switched at that time from an inactivated RVF vaccine to a modified live virus vaccine. It is interesting that in the 1993 epidemic, the predominant clinical presentation was visual impairment in humans and not the hemorrhagic form of RVF observed in the late 70's. In 1993, transmission again began to the south of the Aswan Governorate. Given the 80 percent seropositivity of cases tested, total infections in humans may have been about 2,000 people and about 3 percent of all abattoir workers. Antibodies to RVF were present in 39 percent of domestic livestock.