|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: Respiratory virus infections were traced under experimental conditions among 105 cattle of a naturally occurring shipping fever (SF) epizootic. The cattle were described by Purdy and coworkers. Sequential nasal swab samples were collected before vaccination and on 3 intervals of 7 days, cultured for bacteria and tested for known respiratory bovine viruses. Respiratory bovine coronaviruses (RBCV) dependent on G clone cells were shed by 64 of these cattle before vaccination, and 2 of these cattle shed bovine herpesvirus-1 (BHV-1). Twenty-three cattle contracted RBCV infections during transport so that 87 of them had this viral infection during the initial stages of the epizootic. Eighty-nine cattle developed acute respiratory tract disease or died 1 to 3 days after arrival in the feedlot, and 79 of them had RBCV infections. Other viruses were not isolated from nasal samples collected a day after arrival in the feedlot, but 14 and 21 days later 10 cattle shed RBCV in nasal secretion, 5 other shed BHV-1 and 4 shed bovine parainfluenza-3 (PI-3) viruses. Seven cattle remained clinically normal and never shed respiratory viruses. They had antibody titers of 32 to 256 inhibiting HA of rat erythrocytes by a RBCV antigen containing 16 HA units and 16 units of RDE. Infections with RBCV were a dominant etiological factor in this severe epizootic of SF of cattle.