CHRONIC
PROGRESSIVE LYMPHEDEMA




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Chronic Progressive Lymphedema or CPL, is a condition now noted in all Draft Horse breeds, including Gypsy Horses. It is a problem of which we should all be aware. Sadly, much of the time it goes unnoticed by owners, until the disease has reached advanced stages.

The condition is characterized by progressive swelling, hyperkeratosis and fibrosis. CPL often starts at an early age, progresses throughout the life of the horse, mostly ending with horrible disfigurement and often an early death for the animal. The disease closely resembles the condition known in humans as chronic lymphedema or elephantiasis nostras verrucosa.

We have been doing ongoing research into this problem and have heard from many dealing with it daily in their horses. It is devastating and heartbreaking for their owners and difficult for the horses involved. Dealing with it, is an everyday problem.

Is it hereditary? Some think it is. Others are not sure - yet. Personally, I don't believe it is hereditary in the usual sense of the work, but that all Draft horses have a predisposition to the problem. I was speaking to a lady in another Draft horse breed the other day, and she feels that in her breed, as many as 90% might be affected to some degree. Scary isn't it!

I offer some links below, which will give you some idea of what it entails. You will note that the problem in Gypsy Horses is not mentioned, but other Draft Horse breeds are. However, please know it is known and has been documented, within the Gypsy Horse breed.

Check your horses' feather each and every week. Part the hair down to the skin and all down and around each leg from the hock/knee. Feel his flesh to see if you feel skin folds or grape-like bumps. Grape-like bumps under the skin are another part of this evil thing. They are often very apparent under the flesh above the line of feather. Even if your horse does have it, the sooner you discover it, the better off you will be. Educate yourselves regarding this and let's not put our heads in the sand by not discussing or learning about it. It might be the life of your horse if not dealt with.

For the last few months, I have been doing much ongoing research into the CPL and related problems. I have been forwarded a great deal of interesting material on the subject, by many very knowledgeable people and from many different areas of the world and some of those in the field of Veterinary medicine. A friend in the breed in England, has a Veterinary Surgeon in that country. She is doing much research into the subject and as soon as I receive her permission to post her findings here - I will.

With this at my disposal, I have formed some opinions of my own. As I mentioned earlier, I don't believe it is necessarily hereditary but that all Draft breeds have a propensity to the problem. I used to think that this affected those horses kept in wet conditions, but have lately changed my mind, as many horses with CPL live in dry, sandy areas. Certainly good animal husbandry and vigilant checking of the pasterns and feet is important and of course, knowing just what to look for. The lady Vet in England seems to also agree that common scratches could/might be the start of the problem, but scratches and CPL are very different.

Most certainly, if a horse has scratches - known as Mud Fever/Greasy Heel in some countries, one must be dedicated in taking care of it as soon as possible. Unchecked, over time, this can produce sores, scabs, long horizontal cracks and skin folds. Puffy skin folds, usually at the back of the pastern are a major red flag that the horse has CPL. Later, as the problem progresses, fungal infections are found. If mite infestation is suspected, they must also be dealt with immediately. Tiny mites infest in huge numbers, to feed on the dead and decaying skin. Further infections such as Staphyloccocus and Dermatophilus set in and eventually the horse has the condition we now see as full-blown CPL. One can only guess at just how much these horses suffer for years and years, before they are found dead in their field! Think I'm being dramatic? No - I now know of several well documented cases!

So what does this possibly tell us? Well it does tell us that we should be extremely vigilant in the care of our feathered friends. Draft horses with even small amounts of feather can just as easily be prone to this dreaded disease, as those with plentiful and thick feather. They should be checked weekly for signs of anything unusual. All feather should be parted, down to the skin from the knees and/or hocks, to the heel and inspected carefully, for any signs of a problem. After bathing, feather should be dried completely - preferably with a hair dryer. Any horse showing the first signs of a problem should be removed to a dry area and treated until the condition has completely cleared up. Bedding must also be kept clean and dry and free of mites. There are many remedies for early cases of scratches but for problems which have progressed beyond that, then a course of Antibiotics and/or Anti- inflammatory drugs, should be prescribed. This of course in addition to topical preparations and care.

Has CPL been seen in foals? No, but it has been noted in two year olds. Some still are not convinced it's not an immune system problem. Maybe it is. Could be the immune system is compromised only after the problem has gone unnoticed and untreated for a long time. Don't for a moment think that a horse stamping his feet constantly is just badly mannered. He's probably itching or hurting.

If you notice your horses scratching their legs on any available object or lying down and biting at their feet, look beneath the feather! Horses with something nasty going on under their feather, will often have stained it by rubbing and biting. Horses with incredible itching and pain, caused by mites, scratches and/or CPL, can suddenly become bad tempered or even dangerous to handle.

When you sell a horse or foal, do the owner and the breed a favour, by explaining in great detail, the care these horses need and deserve. Make sure that new owners are fully committed to taking care of them properly.

As always, these are my own thoughts on the subject, but only after putting together tons of information I have received from many knowledgeable people.


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Please note that many Vets are not even familiar with the disease at all and the clinical signs are highly variable so it's up to you to do your homework, check your horses and if necessary - educate your Vets about CPL!


UPDATE

This (below) also makes reference to the fact that the skin of heavy horses is different from light horse breeds as I was speaking of in another post on our forum recently. Experimental work has now shown that when mites are fed on skin scale from heavy horse breeds they will flourish in a "test tube" laboratory environment. Identical mites fed a diet of thoroughbred skin quickly die. There must therefore be factors within the skin of these heavy horses that act to enhance growth and multiplication of mites; as yet these components remain undetermined. Interesting isn't it!

Chorioptic mange in the horse.
Mange in the horse can be caused by a variety of different parasites. However Chorioptic mange which is caused by infestation with the mite Chorioptes bovis, is the disease most commonly identified by owners and Veterinarians. Although this parasite can cause irritation on any part of the horse's body it is colloquially known as "foot mange","leg mange" or "itchy leg" due to it's tendency to effect the lower limbs.

Chorioptes mites are microscopic ectoparasites that are 0.3 - 0.5mm in length. They feed on the most superficial layers of the skin and are found particularly on the lower limbs of heavy horses, especially those with feathered heels.

The mite life cycle.
It takes two to three weeks for the newly laid Chorioptes egg to develop through to a mature adult. Although the mite can survive in the environment, the life cycle can only be completed on the horse. Under ideal conditions of dark, warmth and relatively high humidity the mite, according to some sources, can live for more than two months in the environment. Mites can also survive off the horse in skin debris, such as dried crusts and scabs. Therefore when a case of Chorioptic mange is identified on a yard there is a real danger not only of contagion from any infested animal but also from the horse's immediate environment which of course will include grooming equipment and tack, for up to two months.

Eggs laid by the female mite hatch into the larval stages within four days. The larvae develop into nymphs then adults over the following few weeks. Larvae, nymphs and adults are all capable of feeding actively only twenty-four hours after hatching. The time from egg laying to feeding and disease can therefore be as little as five days.

Mite populations are usually highest in cold weather. During the cooler winter months the mites burrow down underneath the hair particularly around the heels. The thick hair coat of the heavy draught breeds provides perfect conditions for mite development. Cosseted within this niche the mites can survive extreme environmental temperatures due to their own hidden warm, humid microclimate under the protective barrier of hair. Mite numbers drop dramatically in the summer and as they do many of the signs of mange may also appear to abate. However even though the horses may no longer show signs of disease, mites can still be identified in samples taken from around the coronary band by an experienced investigator. Such asymptomatic horses, that remain untreated at the end of the winter, will act as carriers of mites and provide a new focus of infestation later in the year as the temperature drops. There is no doubt that features other than hair coat predispose heavy breeds to mite infestations. Even in working horses whose fetlocks remain clipped and well-groomed mites can thrive on the lower legs.

Clinical signs of mange.
The author recognises a whole range of different clinical signs in horses affected with Chorioptes. Some horses can carry large numbers of mites, usually concealed deep within the hairs of their leg feathers, without ever manifesting signs of disease. Other horses present with very severe mange and harbour only a few mites. This latter group of animals manifesting a grossly exaggerated response to mite feeding activity is probably allergic to the mites.

Whichever parts of the horse's body is affected the first apparent sign of mange is intense itch. The lower legs are common sites of infestation in heavy horses. The horse will nibble accessible areas and commonly foot stamping is observed. Some of these animals show such marked signs as they pick up their feet and flex their legs that they can be misdiagnosed as having strange neurological diseases such a "stringhalt". Foot stamping in Chorioptic mange is a sign of severe discomfort and irritation as well as the horse's frustration at not being able to reach an area of intense itchiness. The whole body is often effected in young foals possibly due to their lower immune status. These animals will rub along suitable surfaces in the stable or paddock and can be mistakenly identified as having allergies. The feeding activity of the mite leads to the characteristic changes in the skin. Where mites feed over extensive areas, the body of the horse can be covered in a fine "oatmeal like" scale. Localised sores on the legs appear as areas of thicken crust, which mats the hair. Trauma to the site from the horse further enhances these changes and produces a compressed protective covering of debris that adds to the mite's microenvironment. Chorioptic mange should be considered as a possible cause of any itchy disease in the horse, especially those involving the legs.

Complications.
As the mites feed, it is not uncommon for them to introduce infection into the skin. Ringworm (dermatophytosis) and bacterial infection with such organisms as Staphylococcus and Dermatophilus can complicate the picture. Even if mite infestations are identified and treated adequately, sores may show only a partial or temporary improvement if the infection is not recognised and addressed.

How do we find the mites?
Mites can be identified by taking skin scrapings, which can be mounted in either mineral oil, or potassium hydroxide Your Veterinary Surgeon should be able to sample any potentially affected areas and assess skin for the presence of mites. Alternatively the advice of a Veterinary Dermatologist with knowledge of equine skin disease, may be sought. In fractious and uncomfortable horses techniques such as skin scraping can be difficult. Scraping scabs off the legs of a stamping Shire horse with a sharp scalpel blade can lead to the collection of more than horse skin! Tape strippings can also be performed to collect mites. Clear adhesive tape placed repeatedly onto the skin can be mounted and examined microscopically.

How do we kill the mites? Where possible not only should an infested animal(s) be treated but all in contact animals and the environment. Therapy can be difficult to apply and can necessarily be expensive in a large horse. Both oral drugs, given by mouth; and topical therapy applied directly to the skin can be used. The biggest problem encountered by any Veterinary Surgeon treating mite infestations in the horse is the limited availability of what are considered to be licensed products. No drug is currently licensed to the author's knowledge to treat Choroptic mange in the horse in the U.K. Many different therapies have never-the-less been shown to be effective but should be used under Veterinary supervision in the light of a specific diagnosis. Ivermectin, which is available as a general equine wormer, can be given following specific protocols by mouth or applied as a solution directly to the legs. Some of the insect repellents more commonly used for conditions such as Sweet itch, particularly those containing permethrin, cypermethrin and benzyl benzoate can be used. However the author would strongly advise against the use of products used for cattle and sheep which can be irritant to the more sensitive equine skin. Sulphur containing solutions including selenium sulphide are highly effective mitacides, although they can be labour intensive and messy to use. The most recent veterinary literature has identified a small animal flea preparation containing fipronil, which has excellent efficacy against mites. This is an expensive form of therapy but as a non-aerosol spray can be applied directly to the legs. In summary, Chorioptic mange is common in heavy cobs and draught horses. These horses are highly predisposed to developing and maintaining mite infestations, not only because of the conformation of their legs but also because of more subtle factors relating to their skin type. Identification and treatment of the mite can be achieved by an experienced Veterinary Surgeon.


UPDATES 2011

As new information comes to light, I try to add it here
This is a must read by Heather Powell, for all owners of draft horses and draft horse crosses.

http://equinemld.com/pages/chronic-progressive-lymphoedema.php

She has visited with staff at UC Davis last year. She is planning another trip to the university. Studies on CPL were done looking into the aspect of a gene as a cause. The suspected gene was found NOT to be the culprit.
There is some suggestion, that possibly our Draft type horses, may require a higher nutrient level than the typical horse. It is quite possible that raising the levels of Lysine, Vit C (and some other nutrients) in the daily diet of especially the growing horse, we may find them not developing damaged elastin. Some Draft horse owners have already been feeding supplements to increase the levels. Maybe it will prove something valuable.
Open communication about the condition; openmindedness with no predjudice to horse owners and individual horses is key to discovering a way to possibly control the nature of the beast.

Two more articles of interest.
http://www.slideshare.net/ayrshirefarm/cpl-in-draft-horses-2417211

http://issuu.com/fourinhand/docs/the_horse_report_cpl_in_draft_horses

In this second link, there are many pages of info. Click on the picture and go from there. Click the arrow to the right, to move to the next pages. I suggest you read 'full-screen'.


Here is an interesting article-
https://www.drafthorsejournal.com/read/winter20102011/doc

In it is mentioned the old diseases of Glanders and Farcy, very similar to some of the CPL we see, however the Glanders and Farcy have an infectious origin. Interesting nonetheless, since it certainly resembles some of the same issues involving damaged Lymph vessels.

Another UC Davis article.
http://www.vetmed.ucdavis.edu/elephantitis/about.html

A very useful article for those who own any breed of draft horses.
http://www.wolfmanorestate.com/PreventingScratches.html


This CPL problem has been quietly covered up and not spoken of, for long enough. We are inviting anyone with any breed of Draft horse, to join our forum, where we share information, compare notes and admit this is a huge problem. No longer can we hide our heads in the sand and pretend it doesn't exist. UCDavis has done much research but their funding has now stopped. It's up to us, the breeders of all Drafts, to come together and share our thoughts and ideas.
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