Simian Hemorrhagic Fever

III. Isolation and Characterization of a Viral Agent

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  • National Institutes of Health, Division of Biologics Standards, Laboratory of Virology and Rickettsiology, Division of Research Services, Laboratory Aids Branch, Animal Conditioning Section, Primate Quarantine Unit, and Comparative Pathology Section, Bethesda, Maryland 20014
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An epizootic of a previously unknown hemorrhagic fever occurred among Indian rhesus monkeys quarantined at NIH in November 1964. Transmission studies revealed that the disease was due to an infectious agent pathogenic only for monkeys. A virus, designated simian hemorrhagic fever, was isolated in the MA-104 cell line of embryonic rhesus-monkey kidney. Of 13 different cell cultures (primary and continuous) tried, the virus produced CPE only in MA-104 cells, grew without CPE in BS-C-1 cells, and could not be propagated in the other 11 cell cultures. The characteristic CPE began as foci of refractile spindle-shaped cells that remained connected to each other by protoplasmic projections forming a network. Biochemical and Biophysical studies revealed that the virus contains RNA and is less than 50 mµ in size, chloroform-sensitive, pH 3.0-labile and relatively heat-stable. Divalent cations, however, enhanced inactivation at 50°C. The virus reproduced the typical hemorrhagic disease in rhesus monkeys. CF antibodies were demonstrated. No relation could be found between SHF virus and some other known RNA viruses.

Author Notes

Present address: Division of Biologies Standards, Laboratory of Pathology.