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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #318038
Title: Bovine respiratory disease model based on dual infections with infection with bovine viral diarrhea virus and bovine corona virus

Author
item Ridpath, Julia
item CONFER, ANTHONY - Oklahoma State University
item FULTON, ROBERT - Oklahoma State University
item BAUERMANN, FERNANDO - Us Forest Service (FS)
item FALKENBERG, SHOLLIE - Elanco Animal Health, Inc
item WELCH, JENNY - Zoetis

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/22/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Bovine respiratory disease complex (BRDC) is the leading cause of economic loss in the U.S. cattle industry. BRDC likely results from simultaneous or sequential infections with multiple pathogens including both viruses and bacteria. Bovine viral diarrhea virus (BVDV) and bovine corona virus (BoCV) are frequently isolated from cattle suffering from BRDC. However, animal models based on infection with either of these viruses alone have had limited success in reproducing respiratory disease. Further, is has been reported that simultaneous infection of cattle with BVDV and BoCV did not result in BRDC. In this study seven infection protocols were compared. Colostrum deprived Holstein calves, at least two weeks of age were exposed to mock inoculum, BVDV alone, BoCV alone, BoCV followed 3 days later by BVDV and BVDV followed 3, 6 or 9 days later by BoCV. Day 3 post infection (pi) was chosen because this corresponds to first detection of viremia for either BVDV or BoCV. Days 6 and 9 pi with BVDV was chosen because the reduction in circulating lymphocytes, typically observed following infection with BVDV, is usually greatest between days 6 and 9. Body temperature was monitored using internal probes and blood samples and nasal swabs were collected, at two to three day intervals, to monitor viremia and changes in circulating immune cells. For calves, which underwent dual exposures, lungs were scored and samples of lung and immune tissue were collected 14 days after inoculation with the second virus. Short-term pyrexia was observed in all animals infected with BVDV. The only infection protocols that resulted in lung lesions consistent with respiratory disease were BVDV followed 6 or 9 days later by BoCV. These lesions were more severe and observed in a greater majority of calves in the BVDV followed 6 days later by BoCV group than in the BVDV followed 9 days later by BoCV group. The observed lung lesions are consistent with a mild to moderate interstitial pneumonia. Immunohistochemistry and virus isolation indicate that sequential infection with BVDV followed by BoCV resulted in prolonged replication of BoCV compared to infections of BoCV alone. These results indicate that while single infection with BVDV or BoCV do not result in respiratory disease, sequential infections of BVDV followed by BoCV can result in gross and microscopic lesions that are consistent with respiratory disease. The window of time in which BoCV infection is most likely to result in respiratory disease coincides with the immunosuppression peak caused by BVDV.