Is Your Horse at Risk for Encysted Small Strongyles?
Can You Naturally Prevent Encysted Small Strongyles?
An Interview with Dr. Gerald Wessner, Holistic Vet
By Jessica Lynn, Earth Song Ranch, Published in Natural Horse Magazine
All horses to some degree, and from time to time may be infested with the tiny parasite known as “Small Strongyles”, as many of them have become resistant to the widely used chemical de-wormer’s over the years, just as there are now penicillin resistant diseases from the over use of that drug in humans.
Many chemical de-worming programs that worked a decade or more ago are not as effective today, and horse owner’s need to change their strategy in regards to not only this parasite but all parasites, taking a preventative and holistic approach as opposed to a chemical shot gun approach monthly or bi-monthly.
If your horse is infected, the seasonal emergence of this encysted parasite varies as to the part of the country in which you live. The small strongyles larva emerges in the late winter and early spring in the northern parts of the country and in fall and winter in the southern parts. When the emergence occurs it shows up most often as non-specific colic like symptoms, and can lead to a very sick horse. The key is prevention!
Thank you Dr. Wessner for taking the time today to answer some questions about Encysted Small Strongyles, they are something we have been hearing a lot about from the equine pharmaceutical companies as being a wide spread problem and we thought we would ask your opinion as to what risk they may pose, if any, to holistically and naturally kept horses.
What are encysted larvae?
The small strongyle is a blood sucker that infests the large intestine. This parasite
has several stages to its life cycle, with the stage 3 & 4 which attach themselves to the wall of the intestine. It is the seasonal mass emergence of this larval stage of parasite (L-3, L-4) from the intestinal wall (the encyst-ment), if a horse is infected, that causes the most problems.
These parasites are smaller then the blood worm (large strongyle) and do not migrate through the tissues and arteries like the blood worm, but do their damage by attaching to and then ulcerating the mucus lining of the intestinal tract.
Are they a problem to horses? If so, why and how?
In my practice over the years I have not seen any horses with this problem. A holistically kept horse is one who has access to fresh clean water, clean hay, preservative free and chemical free feed stuff/bag feed are used; Nosodes are used in place of vaccines, herbal wormers are used in place of chemical de-wormers, fecal counts are done to determine when or if a chemical wormer may in fact be needed.
The horses are kept in large clean paddocks or clean pastures with “friends” , or have plenty of turn out time, and lots of room to move, and they have regular bare foot trims no shoes. Couple that with environmentally responsible fly control practices in place on the property, and non-chemical fly sprays are used in place of insecticides and pesticides.
I think that holistically kept horses are by far healthier, less stressed, have owner’s who are more responsible in their care and do not over use chemical wormers, or over-vaccination as part of their health programs, both of which compromise the horses intestinal tract health and make them more susceptible to parasitic invasions/infestations.
The adult small strongly is a small white worm that resides primarily in the large colon of the horse and does not typically cause the horse any problems when their numbers are low. However, if not controlled, or kept in check, it is the larval stage of the parasite which can cause the problems of diarrhea, inflammation of the bowel with non-specific colic like symptoms, weight loss, and in some cases anemia, as they burrow in to the intestinal wall then are seasonally released in to the intestinal tract.
There is a five stage life cycle to the small strongyles as documented by Dr. D. Craig Barnett, DVM (U of Penn), in his paper Encysted Small Strongyles, it is in the stage L-3 to L-4 when they emerge that could be a problem to the horse when they begin to emerge from the lining of the colon leaving ulcerations in their wake.
Where in the body do they invade/encyst?
The small strongyle larvae attaches itself to the intestinal lining, mainly in the large intestine and the cecum, ulcerating the mucous lining. The adult strongyle is not a problem, it is the eggs they lay and that go through their various stages that can cause the problem once they reach the larva stage, if left untreated, and found at that stage in the gut of an immune compromised horse is where the encystment will happen.
How can one determine if a horse has encysted larvae?
The presence of these immature “worms” (in their larvae stage) can be a little tricky to detect because they are not as yet laying eggs, they are imbedded in the intestinal wall of the horse and do not for the most part show up in regular fecal counts until they emerge. If there is not an active adult population laying the eggs small strongyles cannot be found in a fecal count, only the eggs from the active adults can be found. There is no test that can confirm if your horse in fact has the encysted larvae.
Some of the symptoms of larval cyathostomisis may show up as a subtle decrease in performance, the horse may be slow in shedding a winter coat, and he may have diarrhea (intermittent to chronic), mild colic, or re-occurring non-specific colic, ulcer like symptoms or the horse may be anemic and/or have rapid weight loss.
Are all horses susceptible? What factors may contribute to/cause an encysted larvae problem?
The majority of horses if kept holistically will not be affected by the encysted larvae, as the healthy gut and healthy immune system of a holistically kept horse will naturally repel these invaders. However, all horses are or can be susceptible, from time to time, due to many factors, and depending on where you live can also make a difference. Horses that live in herds in unclean pastures are at risk from an infected carrier horse. Horses that live in the desert would pretty much be immune as the larvae and eggs stay in the pasture grasses, which the desert does not have. In areas of extreme summer heat such as Florida, Texas and Arizona, the larvae are naturally killed off by that heat. In areas with extreme winter conditions such New Hampshire, Minnesota, Wisconsin, and Michigan, with bitter cold, freezing temperatures and snow the eggs and any larvae left in the pastures are also killed off.
Factors that contribute to your horse being susceptible include a compromised immune system which could have been caused by over vaccination or the over use of chemical wormers, but may also be caused by artificial ingredients in horse feeds, treated hays, pesticides and insecticides, including many of those used in horse fly spray; horses being fed or having been fed in the past daily feed through chemical wormers, or monthly wormers because they do not address the horse’s own immune system that has the ability to naturally prevent parasitic infestations, instead the chemical wormers do not allow the horse to develop its own immunity.
In addition horses that are stressed out due to training, showing, stallion’s during breeding season, or mares that are pregnant, may also have a higher susceptibility. Moving your horse to an area of known infestation where he would have the availability of ingesting the eggs and or the larvae from un-clean pasture condition, or ingesting manure from other horses kept in a pasture condition that were infected.
Because your fecal counts show the presence of small strongyles does not automatically mean that your horse has encysted strongyles, it means that there are adults laying eggs, and preventative approaches should be employed.
How can one help prevent an encysted larvae problem?
The number one key to preventing any parasite problem is a healthy immune system which comes from a health “gut” (intestinal tract), along with the monthly or bi-monthly use of herbal wormers which tend to slow down the stag 3 and 4 larvae process, coupled with regular use of a horse friendly, high potency, probiotic blend to maintain the horses intestinal health, especially from spring through late fall in most of the country, it should pass them through so they will not encyst.
What I have found is that herbal wormer blends tend to boost the horse’s intestinal immune system, naturally and help to prevent parasitic infestation. Some of the ingredients in these herbal blends also expel some of the parasites, and some kill them off. Garlic is one of those ingredients.
Use of equine friendly digestive enzymes are also helpful in a natural parasite prevention program.
Chemical wormers are only effective and only eliminate the stage 5 small strongyle once they have emerged and the damage to the intestinal tract has been done. So one must ask, if chemical wormers are so good then why do they not totally eliminate the 1st and 2nd stage larvae and stop the process entirely? And why do they not work on the stages 3 and 4 which are the encysted larvae, or prevent the possibility of encystment?
How can one help a horse naturally eliminate encysted larvae?
One homeopathic product I recommend is Paratox, it will eliminate the parasites by cleaning the intestinal environment; when you clean the environment you clean out the parasites, parasites love to live in “the sewer” if you will, and if you clean that you eliminate their environment, thereby stopping the cycle. Added pro-Biotics and digestive enzymes also help to maintain a clean and healthy gut environment.
The homeopathic Granadum is a vermifuge and will expel tape worms and other worms in horses and is also used for dogs.
Another homeopathic Gaertner Bach is also a remedy for parasites, which can help to expel them.
Diatomaceous earth has been used by some successfully, but may not work for all cases, if it is coupled with good pasture management, clean hay, a healthy intestinal environment, and the regular use of herbal wormers as well as probiotics it can be an intrical part of an overall parasite management program.
What problems do the typical chemical de-worming regimens pose to the infested and the non-infested horse? To the environment?
The typical chemical de-worming regimens are compromising the immune systems of healthy horses, as well as horses who are non-infested, and also preventing all horses from developing their own resistance to the parasites in their own environments. From their over use, especially the daily wormers, it is also creating “super parasites” in that they are becoming drug resistant, and in the moment there are no new chemical wormers to my knowledge that are able to take up the slack. Ivermectin has been around for at least 20 years and is now being found to be ineffective for some of the small strongyles due to its over use.
In my opinion the daily wormer’s are the worst in regards to the environment as they are affecting the birds and small animals who pick through the manure, who are becoming more toxic with their lives being shortened by the chemicals used in the wormers. I have to also believe that in areas of rain and moisture, or near the oceans that some of these chemicals may be getting in to the streams, lakes and rivers, maybe in small amounts but when it all adds up, I am sure it is polluting not only the soil but the water we all drink as well, and making the fish we eat more toxic.
Thank you Dr. Wessner for helping us to better understand what we all need to do as holistic horse caretakers to keep our horses healthier, to prevent parasitic invasions and infestations, as well as letting us know there are some alternatives to the chemical wormers!
Summary Prevention Is the Key:
The only sure way is prevention through proper pasture management and properly maintaining a healthy gut (intestinal environment).
This parasites eggs/larvae is not killed by frost; that is one of those old wives tales, and can be ingested by horses who graze in pastures which are not regularly cleaned. They are killed by extreme heat and frigid winter conditions in parts of the country.
Frequent harrowing and or at least manure pick up a minimum of three times weekly, or more frequent in a pasture/ paddock environment, depending on the space and number of horses is a MUST.
Over crowded pastures and irregular feeding has the effect of setting up a feast-famine situation; feeding off the ground greatly increase the risk of picking up the eggs passed through the manure which will hatch in the intestinal tract. (Horses prefer not to graze around feces but are forced to when in an overcrowded pasture.)
The horses' water supply must be clean and free of feces or run off from infected pastures.
The quarantine and proper management of new arrivals to any ranch or boarding facility, including fecal counts on new horse, can not be taken lightly.
Taking a fecal counts, before introducing new horses to the herd, is critical in controlling this parasite from outside sources. If a new horse is found to be with a high egg count then various natural herbal worming methods or homeopathic remedies available that could be used to reduce that count, and or coupled with a chemical de-wormer in cases of very high counts can in most case eradicate them. At this time Panacure is the only chemical de-wormer that seems to work on the seasonal release of the encysted larvae.