Erysipelas Polyarthritis is caused by the bacterium Erysipelothrix rhusiopathiae, which can cause severe damage to the joints of sheep, leading to arthritis. Polyarthritis can be responsible for significant loss of production, particularly in those sheep suffering chronic arthritis.
Outbreaks of erysipelas arthritis tend to occur following procedures such as lamb marking, mulesing or sheep dipping. The infection usually enters through contaminated wounds and results in inflammation, swelling and fluid accumulation, thus damaging the joint surfaces and resulting in arthritis. Infection post-lambing can also occur if the bacteria enter through the navel. Low numbers of lambs may be affected every year, causing constant low, but significant losses.
Affected lambs have difficulty rising and walking and are obviously lame. The infected joints are hot, painful and swollen and commonly involve knee, elbow, hock and stifle joints. The development of long term chronic arthritis results in poor growth rates and reduced wool production.
Diagnosis may be difficult as a number of different bacteria may cause arthritis in sheep. The bacterium responsible for erysipelas arthritis is commonly found throughout Australia however a veterinarian should be consulted to confirm the diagnosis.
Maintaining a high standard of hygiene at lamb marking and mulesing can minimise erysipelas arthritis. It is recommended that these procedures are carried out in temporary yards and the instruments should be placed in disinfectant between each animal.
The most effective method of protecting lambs at marking is by vaccination the ewes prior to lambing with Eryvac® vaccine.