CASEOUS LYMPHADENITIS - An Update June 2014
Caseous Lymphadenitis is a contagious bacterial infection that appears at lymph gland sites as abscesses. Not all abscesses are CL, but those appearing at typical CL sites (often under the ear, but not always) should be considered suspect and investigated. Because the bacteria Corynebacterium Pseudotuberculosis is resistant to all antibiotics, whether systemically injected into the goat or directly placed into the abscess, Caseous Lymphadenitis (CL) should be considered neither curable nor completely preventable at this time. This article offers an effective alternative method for managing and controlling it, as well as information on the new CL vaccine developed for goats by Texas Vet Lab of San Angelo, Texas.
Caseous Lymphadenitis is a fact of life in meat-goat herds. Like a car wreck, if you drive, your turn will come. If you buy and sell goats or have any significant number of them, you are going to encounter CL. Transmission vectors (ways to spred the disease) run the gamut from insects, birds, and animals to tires, clothing, and the soles of footwear of people who enter your property. Prepare yourself in advance on how to manage and control CL. Unlike Caprine Arthritic Encephalitis (CAE) and Johnes Disease, CL does not damage the health of the goat. CL is primarily a management and nuisance issue.
The CL vaccine made for sheep has not been approved for goats. The manufacturer, Colorado Serum, recommends against its usage with goats because no studies have been done that conclusively prove its effectiveness against CL. Goat producers who choose to use this sheep vaccine on their goats do so at their own risk.
Texas Vet Labs in San Angelo, Texas started selling a CL vaccine made for goats in 2012. My herd was one of the goat herds used to test this vaccine in 2011 for data submission to USDA. I was privileged to announce this new vaccine made specifically for goats in the May 2012 and July 2012 issues of MeatGoatMania, on my website www.tennesseemeatgoats.com, and on ChevonTalk on Yahoogroups, my meat-goat education group on the Internet. It is a very effective vaccine. You should use it with all your goats, including those who have tested positive for CL. See below for additional information.
The basic premise behind vaccines is the introduction of a small amount of the illness-causing (usually) killed bacteria into the animal's body in order to stimulate its immune system to develop antibodies against it. If a goat already has the CL organism in its body, usage of the vaccine can activate the bacteria to form an abscess, usually at or near the injection site. Since laboratory tests for Caseous Lymphadenitis are far from perfect and are affected by the maturity of the goat's immune system (especially in animals under six to eight months of age), you cannot be sure that the goat has not already been exposed to the CL bacteria.
Many people who have Caseous Lymphadenitis in their herds refuse to acknowledge its existence because of the stigma currently associated with having it in your herd. I accept some responsibility for the prevalence of this attitude, because I was originally fearful of this disease and urged culling. However, by taking this approach, we goat producers are hurting ourselves. This new vaccine by Texas Vet Labs gives us a very important tool to eradicate this nuisance disease.
I have done lots of research on CL as it affects goats. When I first began writing about CL, my opinion was to destroy any goat infected with it. Since then I've had many hours of discussions with goat producers, vaccine manufacturers, lab technicians, veterinarians, and others involved in the meat-goat industry. I've learned that there are effective methods available for handling Caseous Lymphadenitis that allow you to keep (and not cull) valuable breeding animals.
For years on ChevonTalk, the Internet meat-goat education and discussion group that I own on Yahoogroups, Dr. Rosemarie Szostak has recounted how she gained control over Caseous Lymphadenitis in her herd. Dr. Szostak, who holds a PhD in chemistry and is also a goat owner, injected Formalin into the abscesses. Formalin, classified as a disinfectant, is a 10% buffered solution of formaldehyde. I long ago concluded that my original rejection of this course of management was wrong. While Formalin usage will not cure CL (nothing will, at present), it does provide an effective management and control alternative, and if used properly, can be effective along with administration of the new CL vaccine for goats.
I used to recommend confining the infected goat, cross-hatch lancing the abscess, draining the exudate (pus), and flushing the cleaned-out abscess with 7% iodine. The problem is that if this procedure is not done at precisely the right time and under the right conditions, the situation deteriorates. If the abscess is lanced too soon, it festers and gets worse. Very little if any pus and (sometimes) lots of fluid is present, since the abscess has not matured to the stage at which the pus is soft enough to be squeezed out. If the cutting is done too late, the risk is that the knot may rupture on its own -- contaminating the other goats and their environment. Either way, this infectious bacteria has a great chance of finding a home on your property.
The right time to open and clean out an abscess is when the hair is just beginning to come off and the knot is becoming soft. The problem is that this seems to occur in differing timeframes in individual goats. (I suspect that this is related to the efficiency of the individual goat's immune system as well as the amount of CL bacteria present in its body.) Some CL abscesses seem to appear almost overnight (they really don't -- producers just haven't been observant enough), while other goats have knots appear very slowly and literally take weeks or months to develop from an undefined mass into a roundish abscess. Some abscesses encapsulate into several knots, while others become a single mass. Pregnant does are a special problem, because you obviously don't want newborn kids exposed to the CL bacteria. If you own many goats, then you will have a huge problem trying to isolate every infected goat, while watching and waiting for that 'right time' to clean out the abscess.
Note: I am NOT a veterinarian and the usage of Formalin is NOT approved for this specific purpose. You may find difficulty in locating and purchasing this product. Like so much of what we producers have to use with goats, this is an off-label/extra-label usage (that does not necessarily mean it is illegal, by the way), so no withdrawal time information is available. Remember, however, that CL abscesses encapsulate; they create a thick wall around the exudate (pus), isolating the infected material from the rest of the goat's body. This is why systemic injections of antibiotics are unsuccessful. The medication cannot get through those thick walls. Therefore, it is highly unlikely that Formalin would be able to migrate to any other part of the goat's body. (Because of the unique nature of this bacteria, direct injection of antibiotics into the abscess doesn't work either.) When the goat is slaughtered and the hide is removed, subcutaneous (under-the-skin) abscesses peel off with the hide. Internal organs that are susceptible to abscesses, such as udders and lungs, go into the offals (trash) bucket as parts of the goat that are not eaten. Such abscesses are very visible in the organs of slaughtered goats, making them easy to recognize and discard.
Step-by-Step: How to Use Formalin
Supplies needed: 3cc Luer-lock syringes, 25 gauge needles, disposable gloves, paper towels, protective eye wear, small plastic Wal-Mart type bags, 7% iodine or equivalent in a squeeze bottle with an applicator tip, #10 disposable scalpels, 16 gauge needles, container into which broken and bent needles can be placed, bleach, bottle of 10% buffered Formalin, small-animal portable electric clippers or hand-operated hair-cutting scissors, and a strong person to hold the goat very still.
The first step is to determine if the abscess is really CL. There are many types of abscesses. If you are in doubt about the abscess, insert a 16 gauge needle attached to a 3 cc syringe into the knot. Try to pull out some of the pus. If you cannot aspirate pus from the abscess and it is located at a lymph gland site, it is probably (but not always) a CL abscess. If you can draw pus through the needle and into the syringe, send it to Bob Glass at Pan American Vet Lab in Hutto, Texas for testing. Bob has developed an inexpensive test that will determine what bacteria is contained within the exudate (pus). You can reach Bob at firstname.lastname@example.org or call him at 1-800-856-9655. I would not inject Formalin into an abscess that can be aspirated. Most types of abscesses need to be cross-hatch lanced and drained. Formalin is not the solution for non-CL abscesses, and if you don't know for sure what the abscess is, do NOT inject Formalin into it.
If you are positive -- absolutely positive -- that the abscess is CL and you decide to inject Formalin, then first feel the knot. If you can move the skin over it, the abscess is NOT ready for Formalin injection (or lancing). If you can get your fingers almost completely around the abscess and pull it away from the body, this means that the abscess is now adhered to the underside of the hide and almost always is soft enough to inject Formalin. (If the pus inside the abscess is still hard, Formalin cannot mix with it and kill the bacteria.) If you wait until the hair is completely off the abscess, the skin will be drawn too tight and too thin and injecting Formalin will probably cause it to rupture. Formalin injection is most successful when the knot is soft, still has hair on it, and can be pulled away from the body by wrapping your fingers around it as described above.
Using a 3 cc Luer-lock syringe (to prevent the needle from blowing off the syringe) and a 25-gauge needle (to produce as small a hole as possible to prevent Formalin backflow), have one or two people hold the goat still. Placing the goat on its side usually allows greater control over the animal's movements. Think of the abscess as a clock face and inject parallel to the body into the abscess at the 12 o'clock position (when the goat is on its feet) so that when the goat stands up, the Formalin is less likely to run out. Be positive that the needle is in the abscess and NOT in the goat's body. Be aware of major artery and vein locations in order to avoid them -- particularly the jugular vein in the goat's neck. While slowly pushing the syringe's plunger, move the needle inside the abscess in a windshield wiper motion to better distribute Formalin throughout the soft pus.
Start with a 3 cc syringe filled with Formalin and fill the abscess until it is firm but not tight. Many times you do not have to use all 3 cc's. Huge abscesses the size of an orange or larger may require as much as 9 cc's of Formalin at first injection. I would not recommend using more than 9 cc's of Formalin per application. Overfilling the abscess can result in swelling around the abscess and short-term discomfort to the goat. Feedback that I've received from people that have injected Formalin indicates that they often use too much Formalin, creating swelling and discomfort for the goat. Hold a paper towel over the injection site when the needle is removed to prevent Formalin from flowing back out, much like a lab technician does when drawing blood. Some goats appear to feel the flow of Formalin, possibly in the form of coldness or pressure. I've seen some goats lick their lips as if they taste it when Formalin is injected in an abscess under the ear, but I believe that they are reacting to the pressure of the abscess being filled rather than tasting it. It is, after all, encapsulated inside the abscess. If this behavior occurs, it is a very short-term reaction. Mostly the goat doesn't like being held. Confinement of the goat in your Isolation Pen is recommended until you are positive that you have the abscess sufficiently filled with Formalin. If you don't have an Isolation Pen, shame on you. Every goat raiser needs one.
Sometimes abscesses occur within abscesses. Check the goat's abscesses for several days after initial injection of Formalin, feeling for soft spots. It will always feel slightly soft around the perimeter of the abscess where it meets the goat's body, as it should; you don't want risk putting Formalin in the goat's body. Inject more Formalin into any other remaining soft spots. The goal is to achieve a hard (embalmed) knot. Formalin combines with and hardens the pus quickly. Once the abscess feels hard all over, leave it alone. Over a period of weeks, it will shrink as a hard black/grayish thick scab develops. Eventually the scab will loosen around the perimeter's edges and either fall off or need to be gently pulled off. The hardened abscess that comes off will have dry pus inside that has been disinfected by the Formalin; dispose of it properly. Fresh pink skin will appear inside a slightly-recessed hole. Flush with 7% iodine or equivalent and let it heal. If the first healing is lumpy and uneven, pull it off and let it re-heal in a smoother fashion so it will hair over and the scar will not be visible. If done correctly, no visible evidence of a CL abscess will exist.
Chest abscesses seem to be the hardest to control with Formalin, since the chest wall allows space for huge knots to develop. In such instances, you must use several cc's of Formalin over a period of multiple days to make sure that the abscess is fully filled with Formalin. Sometimes these large abscesses clear up faster and better if they are lanced. If, when injecting Formalin into any CL abscess, the knot bursts because the skin is already too thin, cleanly cross-hatch lance it with a #10 disposable scalpel, squeeze out all the pus, and flush with 7% iodine or equivalent. Isolation of the animal after any lancing procedure is essential. CL pus is usually but not always whitish/grayish in color and thick (the consistency of toothpaste). It has no odor.
If you get Formalin on your skin or in your eyes or mucous membranes, flush thoroughly with clean tap water. While applying Formalin to the hoof of a goat with hoof rot, I have gotten Formalin in my eye (under my contact lens) and it didn't sting or affect my eyesight. Formalin is odorless, colorless, and the consistency of water.
The plus side of using Formalin to manage CL abscesses is no exposure of the bacteria to either the environment or other goats, no long-term isolation of the treated animals, and less stress on the producer. The negatives include concern about off-label usage, possible objection of some authorities to this application, and as I've learned, the fact that many goat raisers do not use the Formalin properly. Not all abscesses are CL abscesses.
There are articles on my website's Articles page at www.tennesseemeatgoats.com on CL and other types of abscesses, as well as a diagram of lymph gland sites in the goat's body.
You must do your own due diligence and decide which course of action to follow when dealing with Caseous Lymphadenitis. It is my opinion that unless goat breeders want to continue destroying good animals and incurring the financial losses that such decisions bring, then we all had better learn how to manage and control Caseous Lymphadenitis when it appears in our herds. We should all immediately purchase the Texas Vet Labs' vaccine for CL in goats (Jeffers carries it; call 1-800-533-3377) and use it to protect our animals.
A final comment:
While Formalin has its use in controlling CL outbreaks in goat herds, I have discovered that many people are using it incorrectly on several levels: (1) Some folks aren't reading my article closely enough and injecting Formalin at the wrong point in the abscess cycle; (2) Some goat raisers are using too much Formalin and causing swelling around the abscess; and (3) Most seriously, too many goat producers are assuming that every abscess is a CL abscess (NOT TRUE). Formalin should be used only on CL abscesses. Non-CL abscesses should be cross-hatch lanced, cleaned out, and flushed with iodine. The only reason for using Formalin is to contain a contagious bacterium of which too many people are irrationally frightened. With the announcement of the CL vaccine for goats by Texas Vet Labs of San Angelo, Texas in 2012, I am recommending that *all* abscesses, regardless of bacterial origin, be cross-hatch cut and cleaned out, then flushed with iodine. Then every goat -- even those that are CL-positive -- should be given the two-shot series of this new CL vaccine made specifically for goats, then a single injection annually thereafter. See my articles on this new vaccine in the May 2012 and July 2012 issues of MeatGoatMania.
I repeat: Bob Glass of Pan American Vet Lab in Hutto, Texas, has developed and is marketing beginning in 2014 a cost-effective test of the exudate (pus) of *any* abscess to aid producers in diagnosis. Mr. Glass can be reached at email@example.com and his toll-free phone number is 1-800-856-9655. You should avail yourselves of this valuable and inexpensive test.
Suzanne W. Gasparotto, Onion Creek Ranch, Texas 6/8/14
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