Caseous Lymphadenitis is a chronic bacterial infection that causes external and internal lumps in sheep and goats. It is caused by a bacteria, Corynebacterium Pseudotuberculosis, which enters the body through a wound in the skin causing an infection and a slow growing, firm abscess. This infection may also travel to the regional lymph nodes causing a localized abscess there.
The disease is infectious and, under certain circumstances, can spread quickly through your herd. Not all abscesses are caused by this bacteria! In fact, relatively few abscesses are actually C.L. In order for the disease to be present, you must first have the bacteria in your herd or on your ranch. This usually occurs when an infected animal is brought into the herd. Secondly, there must be an entrance wound for the animal to get the bacteria into their systems. It is not necessarily true that an animal with no abscesses will not be carrying the bacteria because the lesions can be on any part of the body including the internal organs. Usually the disease is diagnosed when several animals in the herd are noticed to have a lump or string of lumps in the area of the lymph nodes. Abscesses can be removed or carefully cleaned out and, if there is no lymph node involvement, may not return. A sample of the pus in the abscess or of the animal’s blood can be sent to one of the laboratories, which specialize in diagnosing this type of disease, for analysis. Pus from draining abscesses contains very large numbers of bacteria and the organism can survive for long periods (months) in the environment. This disease is transmittable (although cases are rare) to humans! So if you suspect C.L., let your veterinarian be the one to handle the abscess.