Caseous Lymphadentitis (CL) in Goats

Abscess Before Testing – Right Shoulder

One of our Nigerian Dwarf goats, Honey, recently developed an abscess on her shoulder, causing us to worry that it might be CL.  Although she’d tested negative for CL prior to coming to Bramblestone; and the herd she came from tested negative, we were afraid that she’d somehow contracted the disease.  Our goat herd is closed, so the possibility of contracting CL seemed remote; until I learned deer also carry the disease (so she could have caught it from wild deer) – then I suddenly did a lot of research on CL.

What Is It?

Caseous Lymphadentitis (CL for short) is a relatively new disease in goats (first diagnosed in the United States in the 1970’s and England in the 1980’s) that causes abscesses in both internal and external lymph nodes.  The disease is chronic, has no known cure, and is caused by the bacterium Corynbacterium pseudotuberculosis.  It can spread to the lungs and digestive tract from the lymph nodes; and leads to wasting, mastitis, coughing, respiratory, and neurological problems.

Transmission

The disease is highly contagious, and enters the goat through wounds or mucous membranes.  It can take two to six months for an abscess to appear; and the disease is spread when the abscess bursts and another goat contacts the bacteria.  Once CL gets into the local soil, it’s extremely difficult to eradicate because it can survive for long periods of time and spread via fencing, forage, clippers, straw, and hay.

Symptoms

In goats, abscesses generally first appear externally, and are located around the jaw, mouth, neck, shoulder, upper leg, or knee.  The abscess lump can be as small as an acorn or large as a tennis ball; but the hair covering the abscess will fall out; the abscess will eventually burst by itself, and spread the disease.  The pus from CL abscesses is distinguished by a greenish “cheesy” rather than smooth appearance and odorless nature.  Excessive coughing is a symptom sometimes exhibited by goats with internal rather than external abscesses.

Diagnosis

Although the location of the abscess and greenish – odorless, cheesy pus appearance can be clues indicative of CL, the only way to positively diagnose the disease is with a lab culture.   The veterinarian draws a sample of pus from the wound (preferably before the abscess is even close to bursting), and sends it to the lab for evaluation.

Treatment

Because CL is so contagious, a positive goat can spread the disease from internal abscesses (even if there are no externally open abscesses), and it can pass to humans (although rarely documented); it’s often recommended that any CL positive animal be culled (if the owners wish to maintain CL free herds).

As a minimum, any goat with an abscess should be isolated, and the abscess tested for CL.  If positive, the abscess should be properly lanced and cleaned before it ruptures to prevent transmission.  Depending on the location, it may be best to engage the expert help of a veterinarian before treating the abscess.  Once lanced, the goat should be isolated until the abscess is completely healed – typically for at least 30 days.

The milk from any goat with an abscess should be pasteurized (as a minimum), and if the abscess is on the udder, the milk should be discarded.  Goat kids should be removed from any CL positive doe at birth and raised on colustrum and milk from CL negative does.

Prevention

The best way to prevent CL is not to bring it in – make sure goats come from CL free herds that can show proof of testing and negative results.  Also, any prospective goats should be carefully examined to insure there are no abscesses present.

There are also two CL vaccines that can be used extralabel for goats.  They’re made by Colorado Serum Company (called Case-Bac and Caseous D-T,) but there have been side effects associated with using them on goats (see the excerpt from Colorado Serum Company on using these vaccines on goats below*).  Also, once vaccinated against CL, because the vaccine contains the bacterium, the goat will test positive for CL.

In Honey’s case, we took her to the veterinarian and had a sample from the abscess drawn (it looked white and smooth – not greenish and “cheesy”) and sent for lab analysis. By the following Wednesday, her results came back negative – what a relief!  Since it wasn’t CL, the veterinarian recommended we use hot compresses to see if the abscess would naturally rupture rather than lancing it; and within a week it did.

Honey’s Negative Abscess After Rupturing

So, Honey’s abscess appears to be on the mend, and thankfully we’re not dealing with CL; however, I’m considering vaccinating against it in the future.  I need to investigate the two vaccines more thoroughly, but it currently sounds like a definite option.  I’m curious about everyone’s experience vaccinating their goats.

*Colorado Serum Company often gets a lot of correspondence regarding caseous lymphadenitis (CLA) in goats and questions about using our CLA vaccines (Case-Bac and Caseous D-T) in goats.  There seems to be a lot of interest and misleading information regarding vaccinating goats against CLA.Caseous lymphadenitis is caused by the bacterial organism Corynebacterium pseudotuberculosis.  The two vaccines that Colorado Serum Company makes for CLA are licensed for use in sheep only.  These two vaccines are also the only two commercially available vaccines for combating CLA in the United States.  The vaccine (Case-Bac) is a combination bacterin/toxoid, while Caseous D-T also contains tetanus toxoid and Clostridium perfringens type D toxoid as well. 

The main reason why Colorado Serum Company did not have a label for usage of these vaccines in goats is safety.  Colorado Serum Company originally tested caseous vaccines in goats and noted varying levels of injection site reactions that went from no reactions to swellings about 14 inches in diameter.  There would be associated lameness post-vaccination that would last anywhere from 1 to 30 days.  All of these reactions would be unacceptable to USDA and therefore Colorado Serum Company never pursued a license in goats.  Since Colorado Serum Company was unhappy with the safety profile of these vaccines in goats, we never pursued any further efficacy testing in goats.  Over the years Colorado Serum Company has also received numerous calls from the field from people who have used this vaccine off label in goats.  A fair percentage of vaccinated goats will develop a fever and become lethargic for a period of days.  These goats will sometimes go off feed or have a reduction of feed intake.  Milking does can have a decrease in milk production.  Vaccinating pregnant animals can increase the risk factors.  As in sheep, vaccinating goats that already have CLA will do absolutely no good and will only make the above-mentioned reactions worse.  So you can see why we cannot recommend vaccinating goats with these vaccines.  However, all hope is not lost.  There are other options for goat ranchers.  First of all, I would strongly recommend having any suspect abscesses sampled by a veterinarian and submitted to a veterinary diagnostic lab to confirm if your herd has CLA.  An article by Gezon, Bither, Hanson and Thompson in the Journal of the American Veterinary Medical Association 1991; 198:257-263, reported that over a 16 year period Actionmyces pyogenes was cultured 3 times more often than C. pseudotuberculosis in a particular goat herd with an ongoing history of internal and external abscesses.  The point is – not every abscess in goats is CLA!  If you confirm that you do indeed have CLA in your goat herd I would recommend not treating goats that have abscesses and either selling them or isolating them.  Since there is no commercially available vaccine available for goats you may want to consider having an autogenous vaccine made from a sample of one of the abscesses that tested positive for CLA.  Most autogenous products are whole-cell bacterins.  It has been our experience that a bacterin/toxoid provides a much better immune response.  I don’t know how much protection goats are going to receive from an autogenous bacterin.  You may want to try an autogenous caseous bacterin in a limited number of goats and determine if it works in your goat herd. 

Hopefully this helped answer questions about using Colorado Serum Company Case-Bac and Caseous D-T vaccines in goats and why Colorado Serum Company can’t recommend it.  Currently, Colorado Serum Company is actively pursuing a safer vaccine for CLA that can be licensed for use in goats.