Classical swine fever

Classical swine fever (CSF) is a highly contagious disease affecting swine. It is also known as hog cholera or pig plague. This disease is caused by the Classical Swine Fever Virus (CSFV). This virus belongs to the genus Orthopestivirus within the family Pestiviridae. It is closely related to other viruses like bovine viral diarrhoea. Because it spreads so easily, it is a major concern for animal health. It has even been mentioned as a potential bioweapon.

The way the disease works depends on the specific strain of the virus. Highly virulent strains cause an acute form of the sickness. In these cases, the disease moves very quickly through the animal. Pigs may experience high fever, weakness, and loss of appetite. They might also show purple discoloration on their ears, abdomen, or inner thighs. Severe cases can lead to convulsions or splenic infarctions. These animals often die within 15 days, though some can survive for 2 to 3 months.

Less virulent strains lead to different types of illness. These can cause subacute or chronic infections. These versions of the disease might be hard to detect because the signs are mild. However, they can still cause significant problems for a herd. These strains can lead to abortions or stillbirths in pregnant pigs. Low-virulence strains may also cause piglets to be born with neurologic defects, such as congenital tremors. Infected piglets born to these subclinical sows help keep the virus moving within a population.

Scientists use several methods to diagnose the presence of CSFV. One common method is the Fluorescent Antibody Test (FAT). This test uses fluorescent labelled antibodies to find viral proteins in tissue. Another method is the Enzyme-linked-immunosorbent assay, or ELISA. A serum ELISA detects the antibody response of the host animal. An antigen ELISA looks directly for viral proteins in the serum. Researchers also use RT-qPCR to detect viral RNA. This specific test is very useful for differentiating between different strains.

History shows how difficult it is to manage this virus. Marion Dorset first developed artificial immunization procedures to help protect animals. In the year 2000, researchers Greiser-Wilke and colleagues developed direct genetic typing. They used this to trace the descendants of a large European epizootic from 1997 to 1998. Their analysis showed that the virus in Italy and Spain came from piglet shipments from the Netherlands. Managing the disease requires constant vigilance across different countries.

Many regions around the world have faced outbreaks of CSF. The disease is currently endemic in much of Asia, Africa, and parts of Europe and South America. Some areas have worked hard to be free of the virus. The United States was declared free of CSF on January 31, 1978. Canada was believed free by 1962, and Belgium by 1998. The United Kingdom thought it was eradicated by 1966, but an outbreak occurred in East Anglia in 2000. Other regions like Australia, Ireland, and New Zealand are also believed to be free.

Eradication is a complex challenge for many nations. Current programs focus on rapid detection, diagnosis, and slaughter. In some cases, emergency vaccination is used. This might involve inactivated or live vaccines. In the European Union, countries may use hunting restrictions to limit the movement of infected wild boars. The virus can be introduced to new areas through the transport of pigs or pork products. It can also be maintained in wild or feral pig populations, making it very hard to stop completely.