Experimentally induced respiratory syncytial viral infection in calves.

Calves exposed by intranasal (IN) or intratracheal (IT) or both routes of inoculation to bovine respiratory syncytial (BRS) virus had a transient increase in body temperature for 2 days. Histopathologic changes indicative of pneumonia, along with multinucleated giant cells, were observed in alveolar lumen. The virus was recovered from infected calves, and their serologic response was poor. In a limited serologic survey with 100 serums from cattle in Maryland, low levels of serum-neutralizing (SN) antibody to the virus were prevalent in 38% of the serums.