Effect of experimentally induced type II bovine viral diarrhea virus infection on platelet function in calves
Walz, P.H.; Steficek, B.A.; Baker, J.C.; Kaiser, L.; Bell, T.G.
American Journal of Veterinary Research 60(11): 1396-1401
1999
ISSN/ISBN: 0002-9645 PMID: 10566815 Document Number: 505561
Five newborn calves were inoculated with a thrombocytopenia-inducing type II bovine viral diarrhoea virus (BVDV) isolate (BVDV 890), and 4 calves were used as controls. Platelet aggregation studies and attempts to isolate BVDV from platelets were performed 2 days before, the day of, and every 2 days for 12 days after inoculation. Platelet function was assessed by means of optical aggregometry, using adenosine diphosphate and platelet-activating factor as agonists. BVDV was isolated from purified platelet preparations by use of an immunoperoxidase monolayer assay. Maximum percentage aggregation and slope of the aggregation curve decreased over time in calves infected with BVDV. Bovine viral diarrhoea virus was not isolated from platelets from control calves, but it was isolated from infected calves between 4 and 12 days after inoculation. It is suggested that platelet function may be depressed in calves infected with type II BVDV. Although the mechanism for altered platelet function was not determined, it likely involved an increase in the percentage of aged platelets in the circulation, a direct virus-platelet interaction, or an indirect virus-platelet interaction. Platelet dysfunction, in addition to thrombocytopenia, may contribute to the haemorrhagic syndrome associated with acute type II BVDV infection in calves.