Abstract
A fetal lamb muscle cell line has been isolated in which two strains of Border disease virus replicate well and induce a clear-cut cytopathic effect, thus providing a sensitive and practical assay system for both the virus and neutralizing antibodies. This system enabled us to study some characteristics of Border disease virus in comparison with two other agents responsible for hog cholera and bovine viral diarrhea. Our results indicate that the last virus and the Border disease agent are indistinguishablein vitro.