In 1946 Olafson and associates described gastroenteritis with severe diarrhea in dairy herds in New York state. Some affected animals developed ulcers in the nasal and oral mucosa. Abortions were also seen. Although morbidity rates seemed high, mortality rates were low. Bacteria were not found in blood or tissues that produced the same clinical symptoms in healthy cattle. Through transmission and immunity studies, the ailment was differentiated from rinderpest, which has similar symptoms. The new disease was termed bovine viral diarrhea.
Seven years later mucosal disease (MD) was first described by Ramsey and Chivers in beef and dairy cattle of varying ages in Iowa and neighboring states. Similar to Olafson, they saw symptoms of ulcerative mucosal lesions and diarrhea. Mortality rates were high. It was thought to be a separate disease entity from viral diarrhea. Again, no bacterial agent was found to be associated with the disease. Cross-immunity studies in cattle and cell culture methodologies eventually led researchers to realize that the same virus caused bovine viral diarrhea and MD, and that MD is a possible sequela to BVD infection.
In the 1960s and 1970s it was learned that bovine viral diarrhea virus (BVDV) is closely related to the hog cholera virus and the ovine border disease virus. All three are in the viral family known as Flaviviridae and belong to the genus Pestivirus
Today BVDV infections are seen in all ages of cattle throughout the world and has significant economic impact due to productive and reproductive losses. In the last two decades, recent advances in molecular genetic research has led to an increased understanding of the wide range of clinical diseases associated with BVDV. Learning how to control the spread of the virus is a challenge that still faces researchers.
Kenny V. Brock, DVM, MS, PhD