EPIDEMIC OF RIFT VALLEY FEVER IN EGYPT .1. DIAGNOSIS OF RIFT VALLEY FEVER IN MAN

Abstract

Rift Valley fever (RVF) virus was isolated from 53 of 56 sera collected from patients with a clinical picture of dengue-like illness during the peak of the epidemic of RVF in Egypt in the autumn of 1977. RVF virus was also isolated from the throat washings of 2 patients and the feces of 4, all of whom were positive for virus isolation from the serum. All the isolates were identified by the complement fixation (CF) test. Serological diagnosis of RVF, using paired sera from 16 patients, was made by both the hemagglutination inhibition (HI) and CF tests. HI antibodies were demonstrated in all the acute sera, whereas CF antibodies, which apparently appear later, were detected in only 7 acute and 12 convalescent sera. A longer period than the 12 days in this study must be allowed to elapse between the taking of the paired sera for a definite serological diagnosis to be obtained, especially when CF antibodies are considered.