RIFT VALLEY FEVER

Abstract

Three cases of Rift Valley fever in man are reported. The virus was recovered from the respiratory tract and was transmitted to ferrets by the intranasal route. The experimental disease so produced is characterized by fever, marked pulmonary lesions, and hemorrhagic phenomena. Apparently, the virus of Rift Valley fever belongs to the group of filterable viruses which may gain entrance to the human body through the respiratory tract. The differential diagnosis of Rift Valley fever and influenza is difficult but may be established through animal experimentation. Certain observations concerning the influence of the route of administration on the protective action of immune serum in serum-virus mixtures are presented.