Bovine respiratory syncytial virus infection in feedlot cattle cases in Argentina.

Although bovine respiratory syncytial virus (BRSV) infection has been reported in cattle in Argentina, it has not been associated with pneumonia in Argentina. We report here 5 cases of bovine pneumonia associated with BRSV. Autopsies were performed on 35 beef cattle with gross and/or microscopic lesions of pneumonia from 3 commercial feedlots. Lung samples in 5 of 35 animals were BRSV-positive by reverse-transcription nested PCR. The lungs of 2 of these 5 animals were coinfected with Mannheimia haemolytica, and 1 with bovine viral diarrhea virus 1. Microscopically, the lungs of 3 of the 5 BRSV PCR-positive animals had fibrinosuppurative bronchopneumonia, with or without pleuritis; 2 of the 5 had interstitial pneumonia. We conclude that BRSV is part of the bovine respiratory disease complex in Argentina.