Classical swine fever: how to spot and report the disease

Classical swine fever (CSF) is a contagious viral disease of pigs.

It affects both domestic and feral pigs, but is no threat to humans.

Clinical signs

There are four forms of CSF - acute, chronic, congenital and the mild form in sows. The incubation period for CSF is variable but is usually between five and ten days. The clinical signs of CSF may occur in all of these forms.

The most common forms of classical swine fever are chronic or congenital disease but the signs can be mild and very variable making diagnosis difficult. The disease can also occur in a sub-clinical form, when the pigs don't appear to be sick but are still infectious to others.

The acute form results in very high death rates within four to seven days. Mild and chronic forms may pass undetected and pigs then die from secondary infections. In its acute form the disease generally results in high morbidity and mortality with a high proportion of pigs showing signs of the disease. Symptoms seen can vary but will include some or all of the following:

Acute

• red or purplish skin blotching on ears, snout, limbs and abdomen
• fever (increases in body temperature to 40 oC )
• loss of appetite
• dullness
• pigs will huddle together
• convulsions
• constipation (initially), followed by vomiting and diarrhoea
• gummed up eyes
• coughing

Chronic form

• dullness
• poor growth rate
• fluctuating fevers
• consitpated followed by diarrhoea

Affected animals may show periods of normality following these symptons and can live for more than 100 days after the onset of infection.

Mild form

• abortion or giving birth to stillborn piglets
• surviving piglets may be born with tremors or deformities
• poor growth rates

With this form of CSF, often the clinical signs are not noticable. Sometimes short periods of illness, followed by periods of recovery are seen.

How classical swine fever is spread

Classical swine fever can be spread by:

• direct contact with infected pigs
• contact with body secretions and animal waste from infected animals
• infected material carried on vehicles, equipment, pens, feed, hands, boots, clothing, among other livestock, birds and flies

Human health implications

There are no human health implications becuase the disease is not zoonotic.

Disease control

An outbreak will be controlled in line with the classic swine fever control strategy for Great Britain.

If the disease is confirmed the outbreak will be controlled in line with the contingency plan for exotic notifiable diseases.

Legislation

Classical swine fever is covered by the Classical Swine Fever (Scotland) Order 2003.

Biosecurity

Biosecurity is about being aware of the ways disease can spread and taking every practical measure to minimise the risk of disease spreading. The advice details practical things you can do on your farm to help prevent the introduction and spread of classical swine fever to and from your animals.

The Scottish Government, Scotland's Rural College (SRUC) and Quality Meat Scotland have produced a set of leaflets providing practical advice for pig keepers to prevent disease on their premises.