Respiratory syncytial virus induced respiratory diseases in nursing calves, heifers and feedlots

The authors diagnosed bovine respiratory syncytial virus (BRSV) induced respiratory disease in 6 herds in the daily laboratory work during the 4 years period between 2005 and 2008. BRSV epidemic was found in 2 feedlot herds and in 3 dairy herds. A single case in an imported animal was observed in another herd. Respiratory organs of a died or emergency slaughtered animal were sent for laboratory examinations from each herd. Histological changes suspicious to BRSV infection was found in 5 cases, while BRSV antigens were detected in all the 6 cases with immunohistochemistry (IHC). Secondary bacterial infection was detected in 5 cases (Pasteurella/Mannheimia, Mycoplasma bovis), while virus isolation remained negative in all of the 3 examined cases. According to their observation, BRSV epidemic may occurre also in the months of spring and summer. The use of histological examination together with IHC test was found to be a proper method for the laboratory diagnosis of BRSV induced pneumonia on post mortem examination.