INFECTION BASED ON EXPERIMENTAL AEROSOL EXPOSURE WITH BOVINE RSV IN CALVES

Five conventionally kept calves aged between 17 and 24 days were exper imentally infected with bovine respiratory syncytial virus (BRSV) by a erosol in order to mimic the natural infection route. The calves were killed and autopsies performed 7 days after the first virus challenge. The BRSV isolate used induced tracheitis, bronchitis and atelectasis in infected calves. The only virus which could be isolated from the lu ngs of the calves was BRSV. Ln addition, Mycoplasma bovirhinis was iso lated from the lungs or/and trachea of two calves. The clinical and hi stopathological findings, as well as the detection of BRSV antigens by immunofluorescence in the epithelial cells of lung and trachea, and t he reisolation of the virus from bronchoalveolar lavage fluids of all inoculated calves, provided confirmation of successful infection with BRSV.