HoBi-like pestivirus in 2 cases of fatal respiratory disease of feedlot cattle in Argentina.

HoBi-like pestivirus (HoBiPeV) is an emerging virus that has been detected in cattle and other ruminants. We diagnosed 2 cases of fatal bovine respiratory disease complex (BRDC) associated with infection with HoBiPeV in a feedlot in Argentina. The main findings in 2 steers autopsied were interstitial bronchopneumonia (case 1) and fibrinous bronchopneumonia (case 2). HoBiPeV was detected by RT-PCR in lungs of both animals and by immunohistochemistry in case 2. Phylogenetic analysis showed that both strains clustered within the "Brazilian-Italian" clade. In case 2, Mannheimia haemolytica was isolated from the lung. There is scant information about the contribution of HoBiPeV to the pathogenesis of BRDC. To our knowledge, HoBiPeV has not been reported previously in association with M. haemolytica pneumonia. Our findings further support the involvement of HoBiPeV in cases of BRDC and contribute to understanding the synergy of this etiologic agent in the pathogenesis of BRD, which is critical for the development of appropriate preventive strategies.