Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2009
Publication Date: 1/20/2010
Citation: Blanchard, P.C., Ridpath, J.F., Walker, J.B., Hietala, S.K. 2010. An Outbreak of Late-Term Abortions, Premature Births, and Congenital Deformities Associated with a Bovine Viral Diarrhea Virus 1 Subtype b that Induces Thrombocytopenia. Journal of Veterinary Diagnostic Investigation. 22(1):128-131. Interpretive Summary: Bovine viral diarrhea viruses ( BVDV) are actually two different species of viruses, referred to as BVDV1 and BVDV2, that infect cattle and cause reproductive disease. When BVDV cross the placenta and infect bovine calves before birth it may cause damage to developing brain and bone. This article is a case report of BVDV infection that resulted in unusually severe birth defects in newborn calves. The virus belonged to the BVDV1 species. Some animals were born without front limbs, brain deformities or with uneven alignment of the upper and lower teeth (parrot mouth). When young calves were infected with this virus, it caused a large decrease in blood cells involved in immune response (white blood cells) and blood clotting (platelets). The drop in platelets has not been seen with other viruses from the BVDV1 species. These observations indicate that the BVDV1 strain isolated may be very unusual.
Technical Abstract: Bovine viral diarrhea virus (BVDV) genotype 1 subtype b caused an outbreak of premature births, late term abortions, brachygnathism, growth retardation, brain deformities and rare other skeletal deformities in Holstein calves born to first calf heifers on one dairy. Experimental challenge of three, 2-4-month-old calves that were demonstrated free of BVDV virus and antibodies resulted in thrombocytopenia, lymphopenia and leucopenia. Thrombocytopenia has not been previously reported with BVDV type1 strains and outbreaks of brachygnathism are rarely reported with BVDV.