|My goat was recently diagnosed with caseous lymphadenitis. What is this and is it serious?|
Caseous lymphadenitis, also called “CL” for short, is a chronic contagious disease which affects mainly sheep and goats. It is caused by a bacterium called Corynebacterium pseudotuberculosis and is characterized by abscess formation under the skin, lymph nodes, or internal organs.
Infected sheep or goats with open abscesses represent the main source of infection. The bacteria that drain from an open abscess contaminate the environment and can persist for several weeks to months in the environment. Healthy animals become infected when the bacteria enter the body mainly through superficial skin wounds but may also become infected by ingestion or inhalation of the organism. The bacteria then spread to the lymph nodes or internal organs over a period of 2 to 6 months. Unfortunately, once infected the animal carries the infection for the rest of its life.
Goats usually develop the “external form” of CL which is manifested by abscess formation in the external lymph nodes of the head and neck. The owner will notice one or several small lump(s) under the skin (usually in the head and neck area) which enlarge over time; the majority will rupture and drain greenish-white thick material. Sheep on the other hand, usually develop the “internal form” of CL which is manifested by abscess formation inside of the body.
Affected animals usually eat well at first but then will lose weight over several weeks to months and become very thin.
Therefore, the presence of skin abscesses around the head & neck of small ruminants is highly suggestive of CL. However, a definitive diagnosis can only be made by submitting a culture of the abscess contents. If abscesses are suspected inside the body, ultrasound and/or a blood test (this test detects the presence of antibodies to the CL organism) may be needed to confirm the diagnosis.
Controlling the disease and minimizing its impact can be helped by following these guidelines:
This column is provided by the faculty of the OSU Boren Veterinary Medical Teaching Hospital.