Erysipelas

General

A disease caused by Erysipelas rhusiopathiae, Erysipelas is widespread within the pig industry. The main carrier is the pig itself with up to 50% of a group of pigs being infected without developing clinical signs.

Pathogenisis and Clinical Signs

Infection is spread by contamination of feed, drinking water and pens by oral and nasal secretions. The dung of infected pigs can also spread the disease. Pigs are most susceptible to the disease between 3 months and 3 years of age. Resistance in suckers and weaners will depend greatly on the sow's immunity. Outbreaks can follow periods of stress like changes in nutrition or temperature.

The acute form of the disease has a sudden on set where some pigs may die while others will go off their feed, have breathing problems and develop red blotching of the skin, especially the ears. Diamond shaped red plaques developing on the skin within 24-48 hours are a definite sign of erysipelas. Pregnant sows may abort and neck swelling and vomiting can occur.

Chronic erysipelas may follow the acute form and in this case, skin lesions will slough off and the tips of the ears may be lost. Lameness and enlarged joints causing stiffness are further signs. Pigs may appear quite normal if not affected in the early stages with lameness and weight loss being the only signs. Sudden death can occur when chronic erysipelas is coupled with chronic heart valve damage. These pigs can also become very distressed after exercise or movements.

Diagnosis

Erysipelas should be considered whenever pigs die or suddenly get sick. A high fever (over 40C), skin discolouration, a reluctance to move and eat or those with progressive lameness are signs to watch for. Diamond-shaped red spots and a rapid response to antibiotics help confirm the diagnosis.

For a vet to help in the diagnosis, fresh kidney and liver or spleen and heart blood are needed for laboratory testing.

Treatment and Control

Injections of penicillin should be given except in the case of pregnant sows. In pregnant sows, amoxicillin can be used. In feed or in water medication can also be used to bring an outbreak of acute or chronic erysipelas under control.

Prevention and Control

Vaccinate previously unvaccinated gilts and sows twice, three weeks apart. For sows that have been previously vaccinated, give one dose of vaccinate. Sows need to be given a booster every 6 months. As the bacteria are excreted in faeces, good pen hygiene needs to be ensured.

Note: If a boar becomes affected, ie feverish, then he is likely to become infertile for four to 8 weeks.