Background and history

This bacterium of which two species occur in the pig, Y. pseudotuberculosis and Y. enterocolitica, is found in the intestine. It may cause food poisoning in the human. Infection takes place by mouth and the organism is passed in the faeces for 1 to 10 weeks. It may reside in the tonsils for long periods. It normally causes little or no disease but it has been associated, with outbreaks of diarrhoea in weaned pigs. Y. enterocolitica causes inflammation of the small and large intestines and Y. pseudotuberculosis causes small tiny abscesses throughout the carcass. The main significance of the organism relates to cross reactions that occur in agglutination tests for brucellosis. Pigs that are carrying the organism are likely to react positively. If this is the case it is necessary to determine the point in the rearing system when exposure takes place and break the cycle by management control.

Clinical signs

Weaners and growers

• Y. enterocolitica causes inflammation of the small and large intestines with diarrhoea and
• Y. pseudotuberculosis causes small tiny abscesses throughout the carcass.
• Inappetence.
• Mild fever.

Sows

• N/A

Piglets

• Rare

Diagnosis

The main significance of the organisms is cross reactions that occur when blood tests are carried out for brucellosis. Pigs carrying the organism are likely to react positively. If this is the case it is necessary to determine the point in the rearing system when exposure takes place and break the cycle by management control. Yersinia are easily grown in the laboratory.

Causes

This is a faeces spread disease.

Treatment

There is a response to antibiotics including tetracyclines, synthetic penicillins and fluoroquinolones.