Isolation of bovine respiratory syncytial virus during an outbreak of acute respiratory disease in calves

Bovine respiratory syncytial virus was isolated in secondary foetal calf kidney cell cultures only from non-filtered samples collected during an outbreak of an acute respiratory disease in calves and young cattle. Cytopathic effect became apparent only after is to 25 days of incubation and was characterized by a granular pattern of the monolayer. After adaptation to and several passages in VERO cells, this period shortened to 4 to 7 days and the cytopathic effect (CPE) was characterized by the formation of polynuclear syncytia. The isolate was identified by neutralization and direct immunofluorescence tests. This identification was confirmed indirectly by seroconversion of antibodies to RSV in 60% of palled blood serum samples.