Distinct rotaviruses isolated from asymptomatic calves.

Rotaviruses were isolated following cell culture of the intestinal contents of four non-diarrheic calves. The four isolates were serially propagated in MDBK and BSC-1 cells in the presence of trypsin and produced rotavirus particles morphologically similar to those found associated with diarrhea. They were antigenically related to the Nebraska calf rotavirus (Norden strain) as investigated by immunofluorescence. Three isolates could be distinguished from the reference Nebraska rotavirus by their thermal stability and/or their differential responses to intestinal neutralizing antibodies. Two isolates produced on BSC-1 cells plaques significantly different in size from the reference strain, No significant genomic variations were detected among the isolates.