Pathogenicity of a Non-Cytopathic Bovine Viral Diarrhea Virus 2b Strain Isolated from Cattle in China

Bovine Viral Diarrhea Virus (BVDV) type 2 causes Hemorrhagic Syndrome (HS) in cattle and first emerged in 1990 in North America. In 2014, a noncytopathic BVDV2b strain, SD1301, was isolated and sequenced in China. In order to analyze the virulence of this strain in cattle, five calves were challenged intranasally by spraying 3 ml of virus into each nostril (about 3×106.5TCID50/ml). Results showed that all calves developed clinical signs with rectal temperature higher than the base temperature 1o C at least 1 day, and White Blood Cells (WBC) and platelet counts decreased by over 40%. Gross anatomical examination at necropsy found that the lymph lode leukopenia, lymphopenia, neutropenia, thrombocytopenia. The virulence of the strain isolated suggested that the virus was like that a moderate virulent strain.