Respiratory Infectivity of a Recently Isolated Egyptian Strain of Rift Valley Fever Virus.
Abstract
The respiratory infectivity of a strain of Rift Valley fever virus isolated in Egypt (ZH-501) was compared to an isolate from Uganda (Entebbe strain) and two isolates from South Africa (SA-51 and SA-75 strains). Studies were performed with ICR mice which were infected by exposure to infectious aerosols composed of particles with a mass median diameter of 0.96 micrometers. The respiratory median lethal doses for ZH-501, Entebbe, SA-51 and SA-75 were 2.2, 1.9, 2.6, and 1.9 log(10) PFU, respectively, Although these values are statistically different, the biological implications of such differences seem unimportant. In an additional study of pathogenesis, a single group of mice were infected with 3.1 log(10) PFU of ZH-501 and tissues were assayed sequentially through 96 h postinfection. Between 6 and 30 h, demonstration of an increasing virus concentration only in the lungs indicated that initial replication occurred there; however, determination of histopathologic changes did not reveal evidence of pneumonia. Virus was isolated from the liver by 48 h, and the ultimate outcome of infection was a fulminating and fatal hepatic necrosis. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 10, 1981
- Accession Number
- ADA099266
Entities
People
- John L. Brown
- Joseph W. Dominik
- Robert L. Morrissey
Organizations
- United States Army Medical Research Institute of Infectious Diseases