The Rift Valley fever epizootic in Egypt 1977–1978 1. Description of the epizootic and virological studies

From October to December 1977, an extensive epizootic occurred in Egypt resulting in abortions and increased mortality in domestic animals, and severe clinical disease with fatalities in man. Rift Valley Fever (RVF) virus was isolated and identified as the causative agent. In humans, acute febrile, encephalitic, ocular and fatal haemorrhagic diseases were documented as resulting from RVF virus infection. A retrospective serological survey indicated RVF was recently introduced into the area. The 1977 epizootic extensively involved five Governorates. In the summer and autumn of 1978, epizootic RVF reappeared in Egypt and spread to previously uninfected areas. Virological, serological and epidemiological studies, and factors related to the spread of RVF are discussed.