Swine Fever

Swine Fever, highly contagious, fatal, haemorrhagic, viral disease affecting pigs, also known as hog cholera. It is caused by two unrelated viruses: classical swine fever (CSF) and African swine fever (ASF).

The condition is treated with extreme caution by the international health authorities because it causes severe economic damage. All pigs contracting acute versions of CSF or ASF (which have many indistinguishable symptoms) can die within five days and even those with the least virulent version of CSF eventually die within a year, even after possible partial recovery.

Swine fever is spread from pig to pig through oral and nasal secretions or contaminated recycled feed. The CSF virus, however, can be shed for 10 to 20 days following infection and transmitted to other pigs through contaminated vehicles, human beings, syringes, or even by air. In each instance the chronic condition induces fever, depression, weight loss, diarrhoea, pneumonia, and, inevitably, death in 90 per cent of cases.

Protection against CSF is also made difficult by the tenacious infective quality of the virus, which can survive for two to four years in frozen carcasses. As a result, many governments refuse to accept pig-meat imports from countries with inadequate controls; these countries are unlikely to become approved exporters of live pigs or pig-meat because of poor internal restraints on disease.

One of the best-regulated international trading zones is the European Union (EU). However, despite the rigid administration of an EU slaughter policy on both diseased and contact animals, which was introduced in 1980 with the aim of eliminating both strains, CSF still occurs naturally in parts of Italy and Germany. After ASF spread into Europe in 1957 it became established among wild pigs in isolated areas of north-west Spain and Portugal, and also in Sardinia. As a result, the EU's domesticated pig herd still suffers from sporadic outbreaks of both CSF and ASF. Control has recently been made more difficult as a result of the discontinuation (on cost grounds) of internal border controls, following the adoption of the single European market in 1993.

The most recent outbreak of ASF was recorded in Spain, Portugal, and Italy in 1993, and epidemics of CSF swept Germany, Italy, France, Belgium, and the Netherlands as recently as 1993-1994, and Romania in 2007. In 2000 a minor outbreak of CSF in eastern England resulted in the slaughter of 20,000 pigs. A typical protective strategy is to restrict the movement of breeding pigs, pig-meat, and pig offals from areas which are known to harbour the disease. Some countries establish a surveillance area around infected premises, which are then cordoned off and all animals affected, or suspected of being affected, are slaughtered. In many cases compensation for infected pigs is paid at half the market value, and the value of pigs suspected of having been in contact with disease paid in full.

During the 1994 CSF outbreak in Germany and the Netherlands, some 91,702 infected pigs were killed on 55 farms and the preventive slaughtering of 231,590 pigs was carried out on a further 326. The estimated administrative and slaughtering cost was £125 million. No exact calculation of the total economic damage has been made.