Evidence of infection of sheep and, to a lesser extent, cattle, with Rift Valley fever (RVF) virus was obtained from a sero-epidemiological study conducted on four farms in the Chisamba area of the Central Province of Zam bia. This area was affected by an epizootic of RVF in the 1973/74 rain season; clinical cases were again reported during the 1977/78 rains. The results suggest that RVF virus is established enzootically in this area and that domestic sheep and cattle may be acting as a reservoir of infection.

The re-emergence of rinderpest virus in East Africa in 1979 caused widespread outbreaks of disease and subclinical infection throughout the region until mid-1983. Subsequent massive emergency vaccination campaigns have been successful in eliminating clinical rinderpest from Tanzania and preventing its spread southwards. Unfortunately the virus is still endemic in north-eastern Uganda and has recently caused epidemic outbreaks with high mortality in cattle in that country. In Kenya, buffaloes (Syncerus caffer) in and around the Masai Mara game reserve have developed antibodies to rinderpest virus as recently as late 1984. Although there have been no outbreaks of clinical disease in Tanzania or Kenya from April 1983 to the end of 1985 this serological evidence plus the increasing incidence of clinical outbreaks in Uganda indicate that rinderpest virus still threatens East Africa. The substantial aid which has been provided to the region for rinderpest control must be maintained.