Caseous Lymphadenitis

Caseous Lymphadenitis is one of the most common and serious diseases of goats and sheep worldwide. Characterized by repeat abscesses of the lymph nodes, Caseous Lymphadenitis (CL) is caused by Corynebacterium pseudotuberculosis . It can infect nearly any animal, and is a zoonotic (although there has never been a case of human CL in the United States). It is impossible to cure and a pain to exterminate.

How do I know if my goat or sheep has CL?

The most common symptom of CL is an external abscess. They are often under the jaw or below the ear, but can be at the site of any lymph node. Although it usually takes at least three weeks after exposure for an abscess to occur, once present they grow extremely fast and very large. If you notice an abscess near a lymph node, contact your veterinarian as soon as possible to lance it. Cleaned well, it will have less chance of recurring, it will not contaminate the yard, and you will be able to run a serum culture to determine if it is, in fact, Corynebacterium. Puncture wounds and other diseases cause abscesses, so don’t automatically assume the worst.

Other symptoms are weightloss/unthriftyness or a chronic cough. Either of these can be signs of internal abscesses (often on the liver, kidneys, or lungs). In the case of a goat or sheep that you suspect may have CL, isolate them--coughing can spread CL to other goats--and contact your vet to rule out other possibilities (such as worms or a respiratory infection). Antibiotics may help to slow down the spread of the disease, but once an animal has it internally, it's future is bleak. The abscesses will continue to spread and eventually, euthanasia is usually your only option.

There are blood tests for antibodies to CL, but they are not very accurate. There is a good chance of false negatives with the ELISA, especially if the goat does not already show symptoms. Although this can be an important step in managing a large herd, please use bacteria cultures to more accurately identify infected animals. Even cultures may be contaminated, but a positive result is incriminating.

What should I do if my goat or sheep has CL?

Isolation is key to keeping your herd. If a single goat gets an external abscess, but you treat and clean it well, you may have no further problems. On the other hand, if the abscess is allowed to burst on it's own in the yard, the bacteria can survive in wood, dirt, bedding, and food for years.

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