The two virus species Pestivirus A (also Bovine Virus Diarrhea Virus 1 , BVDV-1 ) and Pestivirus B (also Bovine Virus Diarrhea Virus 2 , BVDV-2 ) belong to the genus Pestivirus , which only includes animal pathogens of the Flaviviridae family . The BVDV causes a dangerous diarrhea in cattle , especially calves, the bovine virus diarrhea ( mucosal disease ) . It occurs in a cell-damaging (cytopathic) and a non-cytopathic form. The two forms are based on two different genotypes that differ only in a single base pair. Genotype 1 (non-cytopathic BVDV) is much more common (Europe: 89% of the viruses detected, North America: 64%) than the more aggressive genotype 2 (cytopathic BVDV).
The BVDV is closely related to the causative agent of classical swine fever ( Pestivirus C ) and the border disease of sheep ( Pestivirus D ). It belongs to the single-stranded RNA viruses and has a round shape with a diameter of about 40 to 50 nanometers. It is already inactivated by mild disinfectants and surface-active substances (e.g. household cleaners) . Outside the host, it is inactivated after a short time in a warm environment, but in cold and damp conditions it can remain infectious for several weeks.