Isolation of Low-Virulent Mouse Hapatitis Virus from Feces in Infected Mouse Breeding Colony

Abstract

A virus having physicochemical properties common to Coronavirus was isolated from the feces of 4-week-old mice of a breeder colony with high positivity for antibody to mouse hepatitis virus and Sendai virus but without any evidence of illness. The virus rapidly multiplied with cytopathic effect accompanying syncytia formation on DBT cell culture. The isolate was shown to be capable of producing fatal hebatitis in weanling mice only when cortisone was given shortly after inoculation. By complement fixation test and immunofluorescence a cross-reaction was observed between the isolate and a virulent strain, MHV-2. In virus neutralization test using DBT cells, however, some antigenic discrepancy was evidenced between the two viruses.