Observations on two strains of bovine malignant catarrhal fever virus in tissue culture.

Two cell-free strains of bovine malignant catarrhal fever (MCF) virus were examined by fluorescent antibody staining and for cytopathogenicity in secondary bovine thyroid (BTh) and secondary bovine kidney cell cultures, and in a bovine embryo lung cell line. The hartebeest-derived strain (K30) induced syncytia and intra-nuclear inclusions in all three systems, whereas the widebeest-derived strain (WC11) induced intra-nuclear inclusions in all systems, but syncytia in only BTh cells. Fluorescent antibody staining detected virus in tissue culture at least 24 h before the appearance of cytopathic effect.