Ten strains of Rift Valley Fever virus were isolated from serum samples from acute human cases collected during an epidemic of undifferentiated febrile illness. Post-mortem samples were obtained from two fatal infections. Severe liver necrosis, interstitial pneumonia and myocardial degeneration were seen. Rift Valley Fever virus was isolated from post-mortem samples of liver, cerebro-spinal, pericardial and pleural fluid and from a throat swab. The virus was also isolated from nasopharyngeal washings suggesting that direct transmission from man to man may be possible.