A highly contagious epizootic disease of pigs, also known as hog cholera. The causative agent is a virus in the family Flaviviridae, genus Pestivirus. Due to its significant economic impact, this disease is the subject of statutory controls in a majority of countries. It has been eradicated from many areas, including the United States, Canada, Australasia, and most parts of Europe. Clinically and pathologically, it closely resembles African swine fever, which is caused by an unrelated virus.