The history of bovine viral diarrhea is a short, albeit busy one. BVD was first discovered in 1946 in North America. Another, more fatal disease was described in Canada a little bit later – this disease is now referred to as mucosal disease.
The first case in the USA displayed symptoms like leukopenia, fever, nasal discharge and gastro-intestinal erosions. The Canadian based mucosal disease was described as a very severe disease with a fatal outcome. In 1957, the first isolation of the virus’ viral agent was performed. The following decade, a cattle disease with the same clinical presentation was described in Germany. In 1961 it was demonstrated that the causative viral agents of both diseases, and of the fatal mucosal disease, were the same. By now it is known that the mucosal disease is caused by a super-infection of a cytopathic strain of BVDV in a persistently infected animal, a PI. PIs are always infected by a non-cytopathic strain of BVDV. The first isolation of a cytopathic strain of BVD in 1961 was the basis for the first mass production of a live-modified vaccine against BVDV. A newly recognised form of severe haemorrhagic disease was described in North America in the 90s and was associated with a distinct genotype, BVD type 2, which is now also present in Europe.