By Dr Andrew Tucker, CS Vet
Erysipelas is an infectious condition of pigs caused by the bacteria Erysipelothrix rhusiopathiae. Erysipelas is found worldwide and is passed into the environment from the faeces and urine of affected pigs. It can survive in soil under the right conditions for long periods of time and infected birds and rodents can provide a reservoir of infection to the pig population. Infected fishmeal can also be a source of infection to a pig herd. The bacteria enters the pig via the tonsils, gastrointestinal tract or through skin abrasions. Multiplication then results in a septicaemia within one to seven days of infection.
Recovered animals retain lifelong immunity to the particular strain, which they were exposed to, and remain as carriers of Erysipelas for life.
Erysipelas can infect humans with abattoir workers being at highest risk. In humans it usually presents as a localised inflammation of a finger.
How do you know if it’s on your farm?
Three different forms of the disease are described, dependent on how long the Erysipelas takes to have its effect on the pig. The very quick form can result in a collapsed pig with fever but most commonly is seen only as sudden death. The quick form takes 12 to 48 hours to have its effect and again results in fever. The pig may show signs of blotching on the skin and after 24 hours will start to develop the typical red/purple diamond shaped skin lesions associated with this disease (Diamond Skin Disease). Again at this stage of the disease pigs may die while sows may return to service or abort.
The slow form of the disease can result in pigs completely recovering. In this form the skin lesions are often very obvious, sometimes turning black before recovering. Varying degrees of swollen joints and lameness can be seen as the bacteria can be localised in joints. Older animals can show signs of various heart problems due to damage done to the heart’s valves.
The skin lesions seen are typical and diagnosis is often made on them alone. Various laboratory tests can be done to confirm the diagnosis, particularly in cases where the skin lesions are not present.
How do you treat or prevent it?
Treatment with antibiotics is very effective. A full course is important to avoid the Erysipelas persisting and causing the slow form of the disease. Prophylactic treatment of in contact pigs is often needed to stop the spread.
Eradication is at this stage not practicable, Erysipelas is too widespread in the environment. It is however advisable to clean out and disinfect pens, particularly where disease has been present. Modern buildings and pathways between buildings to avoid any contact with soil reduces the incidence of disease greatly.
Vaccination is widely practised as a means to prevent clinical Erysipelas in breeding stock. Timing of the vaccination is dependent on the on-farm situation and the product being used.
Pig Diseases – D.J. Taylor; Diseases of Swine – Straw, Zimmerman, D’Allaire, Taylor