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ARS Home » Research » Publications at this Location » Publication #77712
Title: ACUTE PULMONARY LESIONS IN SHEEP EXPERIMENTALLY INFECTED WITH BOVINE VIRAL DIARRHEA VIRUS

Author
item MEEHAN, JAMES - HAZLETON WI, MADISON, WI
item Lehmkuhl, Howard
item Cutlip, Randall
item Bolin, Steven - Steve

Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Respiratory tract disease is a leading cause of economic loss to the cattle industry resulting in the annual loss of millions of dollars. Bovine viral diarrhea virus (BVDV) is known to produce enteric disease in cattle but the role of this virus in respiratory tract disease is far less clear. While using sheep as a model to study respiratory syncytial virus (RSV) infection, we observed more severe lung lesions in sheep inoculated with RSV containing a noncytopathic BVDV. In order to evaluate the contribution of the BVDV to the lesion production, lambs were inoculated with the BVDV prepared from the RSV inoculum. The sheep developed a transient decrease in white cell count and blood platelet counts decreased but remained within normal limits. Lung lesions consisted of moderate swelling with multiple areas of cell death and bleeding. Degenerative changes were present in cells of the air sack, cells lining the blood vessels, and macrophages in blood vessels of the lung. This is the first time these changes in the lun have been described. The results of our study show that BVDV can cause lesions in the lung and therefore should be considered as a respiratory tract pathogen as well.

Technical Abstract: Six 6 to 8 month old lambs without antibody to pestivirus, as determined by serum-virus neutralization tests, were inoculated intranasally, transtratracheally, and intrabronchially with an isolate of non-cytopathic bovine viral diarrhea virus (ncpBVDV). Two control sheep were inoculated with fluid prepared from non-inoculated cell cultures. Sheep were monitored daily for clinical signs and bled by jugular venipuncture for determination of white blood cell and platelet counts and for buffy coat collection. Two infected sheep were euthanatized on post-inoculation day 2, 4, and 6. Control sheep were euthanatized on post-inoculation day 2 and 4. All sheep exhibited transient leukopenia and/or lymphopenia. Platelet counts decreased but remained within normal limits. Bovine viral diarrhea virus was isolated from buffy coats and tissues of all sheep. Pulmonary lesions consisted of moderate edema with multifocal alveolar septal necrosis and hemorrhage. There were infiltrates of mononuclear inflammatory cells. Additionally there was morphologic evidence of platelet activation and pulmonary intravascular macrophage stimulation. Degenerative changes were present in alveolar epithelium, endothelium, and pulmonary intravascular macrophages.