Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/30/2010
Publication Date: 10/1/2010
Citation: Sacco, R.E., Waters, W.R., Palmer, M.V., Nonnecke, B.J. 2010. Modeling Bovine Respiratory Syncytial Virus Infection [abstract]. The Association for Veterinary Teaching and Research Work. p. 6. Interpretive Summary:
Technical Abstract: Bovine respiratory disease (BRDC) is a leading cause of morbidity and mortality in calves in U.S. beef feedlots. Furthermore, it is the leading cause of weaned dairy heifer mortality and one of the primary causes of mortality in pre-weaned dairy calves. While the mechanisms leading to BRDC remain to be elucidated, it likely involves interactions of infectious agents, host immune modulation, and physiological stress due to management practices. Viral infection is almost always a primary infectious insult. Common viral agents include bovine herpes virus (BHV)-1, bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), and bovine respiratory coronavirus (BRCV). Subsequently, opportunistic bacterial infections result in an exacerbation of lung pathology. Primary bacterial agents in BRDC include Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis. We have developed two models of viral infection, intratracheal and aerosol, using BRSV in calves up to 2 months of age. Earlier studies involved the use of intratracheal inoculation. In that model, 60-70% of the animals typically developed gross and microscopic lesions indicative of BRSV infection. More recently, we have developed an aerosol challenge model for BRSV, which more consistently produces lesions characteristic of natural BRSV infection in calves. Gross lesions included areas of multifocal consolidation and atelectasis. Microscopically, there was a necrotizing bronchiolitis and interstitial pneumonia with syncytial cells observed. This model will be useful for studies of viral-bacterial interactions as well as testing novel vaccines for BRSV.