The isolation and characterization of a strain of infectious bovine rhinotracheitis virus from stillbirth in swine.

A virus, designated 5089, which was isolated from tissue samples from two stillborn pig fetuses was identified on the basis of its morphology, cytopathology, physiocochemical and serological characteristics as a strain of infectious bovine rhinotracheitis (IBR) virus. Three piglets inoculated intranasally with 5089 virus did not respond serologically and no virus was isolated from their tissues at intervals after inoculation. They showed neither clinical signs nor significant lesions. A colostrum deprived calf which was inoculated intranasally with the same virus developed clinical signs typical of the respiratory form of IBR and the virus was reisolated on several occasions from nasal swabs.