Classical Swine Fever Virus (CSFV)
CSFV (previously called hog cholera virus) is a member of the family Flaviviridae, genus Pestivirus. The virions are spherical, 50 nm in diameter, and consist of a tightly adherent lipid envelope covered with indistinct peplomers surrounding a spherical nucleocapsid with probable icosahedral symmetry. The single-stranded RNA (ssRNA) of the virus is infective and is about 12.5 kb long. Although CSFV can replicate in non-porcine cells, porcine kidney cells are used most frequently for virus growth. Virus replication is restricted to the cytoplasm of the cell and does not result in a cytopathic effect. The first progeny virus is released from the cells at 5-6 hours post-infection. Virion assembly occurs on membranes of the endoplasmic reticulum, but performed capsids and budding are not seen. Instead, fully formed virions appear within the cisternae of the endoplasmic reticulum and are released via exocytosis or cell lysis.
Pigs and wild boar are the only natural hosts of CSFV. Incubation period of CSFV is 2-14 days. Field strains of CSFV vary widely in virulence. Strains of high virulence induce acute disease and high mortality, whereas moderately virulent strains generally give rise to subacute or chronic infections. Postnatal infection with low-virulence CSFV results in mild disease or subclinical infection. However, such low-virulence strains can produce mortality in porcine fetuses and new-born piglets.
Classical swine fever (CSF) is an economically important contagious disease of swine world-wide. It was first recognized in Ohio in 1933. The disease occurs in much of Asia, Central and South America, and parts of Europe and Africa. Many countries are free of the disease among which are Australia, Canada, Ireland, New Zealand, Scandinavian countries, Switzerland, and the United States. The last outbreak in the Netherlands occurred in 1997. Total cost of the effort to eradicate CSFV amounted about 490 million USD.
Several countries, including those of the EC, have eradication programs in force, based on rapid diagnosis and stamping out of infected herds, supplemented by other control measures. Despite this efforts, CSFV has still not been eliminated in many countries. This may be accounted for by the high density of pigs in certain areas, the movement over long distances of pig and pork products, and a frequent inability to trace the source of outbreaks. CSF is classified as an OIE List A disease.
More information about CSFV can be obtained:
[ CSFV |
ASFV |
PRRSV |
ADV |
PPV |
SVDV |
FMDV |
VSV ]
