|Briggs, Robert - Bob|
Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/1998
Publication Date: N/A
Technical Abstract: Pneumonia of cattle associated with shipping fever (SF) results from stress favoring respiratory viral and bacterial infections. Parallel samples of the lungs of 10 cattle that died in a SF epizootic 1 to 2 days after transport were examined by quantitative virological and bacteriological tests. Six of the 10 cattle shed respiratory bovine coronaviruses (RBCV) in nnasal secretions before and 3 contracted this infection during transport. Other viruses were not detected in their nasal secretions. The pneumonic process affected about 1/2 to 2/3 of each lung. The plaque forming units of RBCV per gram of the pneumonic lung of 9 cattle ranged from 8.0 X 10**3 to 5 X 10**6. All 10 samples had 1 X 10**5 to 1.4 X 10**9 colony forming units of Pasteurella haemolytica of serotype A1 (Ph1). Cells of the 9 RBCV isolation-positive lung samples contained RBCV antigens in indirect immunofluorescent (IFA) test with antiserum against RBCV. Nasal and lung samples of animal #63 were negative in virus isolation and the IFA test fo RBCV. All lung samples tested IFA negative for antigens of bovine viral diarrhea virus. These findings furnish evidence that RBCV infections played an etiological role in combination with Ph1 in the pathogenesis of these fatal cases of SF.