Diverse outcomes of bovine viral diarrhea virus (BVDV) infections in a herd naturally infected during pregnancy

A case study

Abstract

A beef producer purchased pregnant Angus crossbred cows with nursing calves. The purchased cattle, their nursing calves, and subsequent born calves were not initially tested for bovine viral diarrhea virus (BVDV), nor was there a history of vaccination. Bovine viral diarrhea virus subtype 2a was later isolated from an aborted bovine fetus estimated to be 6.5 months gestational age. The fetus had multiple congenital malformations including arthrogryposis, kyphosis, scoliosis, polydactylism, and cardiac overriding aorta. Testing by immunohistochemistry and virus isolation resulted in the detection of potentially persistently infected cattle, including a yearling and a calf born during the same calving season as the aborted fetus. Viruses isolated from the malformed fetus, the yearling, and the calf born during the same calving season were identical. The malformations observed in the aborted fetus were similar to arthrogryposis multiplexa (AM) and contractural arachnodactyly (CA), diseases associated with genetic defects in the Angus breed. The fetus was tested and found negative for the genetic defect linked with AM and CA. This case illustrates that suspect malformations should also be tested for BVDV, and underscores the potential for disease after failed or inadequate biosecurity.