In 1992, two BVD genotypes, or strains, of the virus were discovered. However, with the incidence of BVD on the rise, researchers are devoting more resources to produce still better vaccines and develop additional diagnostic tools to identify infected animals. Dr. Chris Chase of South Dakota State University's Veterinary Science department says BVD is not just a problem in cattle. We're certainly seeing more of the disease at our diagnostic lab.
Acute infections result from direct exposure with an infected animal.
Once infected, the clinical signs of acute illness are typically mild, according to Kenny Brock of Auburn University College of Veterinary Medicine, Pathobiology department. Mild fever and diarrhea may be observed following an acute infection with the virus in calves or cows. During this time, the fetus' immune system is developing. If the gestating cow is exposed to BVD, the fetus is also exposed. The immune system of the fetus does not recognize the virus as a pathogen, but rather as part of its immune system.