Classical Swine Fever Virus

Abstract

Classical swine fever (CSF) is a highly contagious transboundary disease of swine that occurs in an acute, subacute, chronic, or late onset form. It is caused by an enveloped positive-stranded RNA virus (CSFV) belonging to the genus Pestivirus in the family Flaviviridae. Acute CSF is characterized by high fever, severe depression, anorexia, diarrhea, multiple superficial and internal hemorrhages, central nervous disorders, and high morbidity and mortality. In the chronic form, the signs of depression, anorexia, and fever are less severe than in the acute form. However, animals eventually die after a few months. Transplacental infection with viral strains of moderate virulence can result in persistently infected piglets, which appear clinically healthy at first but later on develop the disease and die several weeks or months after birth (late onset form). During their lifetime, they constitute a dangerous virus reservoir. Due to their severe economical impact, outbreaks of CSFV infections are notifiable to the Office International des Epizooties (OIE) in Paris, and they are usually dealt with by implementing rigorous control measures, that is, the killing of all infected pigs and herds suspect of having contracted the infection. Vaccination is banned in countries free of CSF. In countries where CSF is endemic, vaccination is used in order to minimize the economic impact of the infection.