The need for a paradigm shift in the control of classical swine fever
Classical swine fever (CSF) is one of the diseases of pigs that cause major economic losses, in particular in countries with an industrialised pig production. It is listed as one of the highly contagious list A diseases for suidae. The CSF epidemic in the Netherlands in 1997/1998 illustrates the economic losses and the ethical dimension of the disease. More than 12 million pigs had to be killed and destroyed and the total sum of direct losses amounted to US $ 2.3 billion. However, only less than 10 % of the pigs were directly affected by the disease. During the last decade large scale culling was also conducted in Austria, Belgium, Czech Republic, Germany, Italy and Spain. The CSF policy in the European Union (EU) defines freedom from CSF as freedom from CSF antibodies. Pigs with CSF antibodies are assumed to be a risk factor. Consequently, there is a general request for seronegative pig populations to permit the international trade of pigs and pig products. Vaccination is impossible since the antibodies in vaccinated individuals would be interpreted as “proof” for the presence of CSF. To keep a population seronegative, killing and innocuous disposal of all pigs within a specific radius around a CSF outbreak (culling) is a common practice in areas with a high pig density. This strategy, which is now about 20 years old, is being challenged by two fundamental changes. The first important change is public perception. While stamping out the virus still remains the ultimate goal, the culling of healthy pigs has become an important ethical issue. Secondly, significant advances in diagnosis and modern vaccines now allow for a selected culling of infected herds. Modern diagnostic tools (PCR) enable veterinarians to differentiate between infected and uninfected pig herds. Based on PCR and potent vaccines a paradigm shift in the control of classical swine fever is therefore possible today. This paradigm shift is an ethical obligation in order to avoid the killing and innocuous disposal of healthy animals.