April 2012
For What It's Worth

Meningeal Worms

This situation may look innocent, but deer, slugs and the meningeal worms are lurking in the low lying swampy areas within these woods.  As the goats eventually graze the forages low, they risk ingesting the meningeal worm and the potentially fatal situation begins.


In Specific Environments, Extreme Danger to Small Ruminants and Camelids

Spring is not the season to worry about the following problem, but it is a good time to create a proactive knowledge. Keep in mind this problem is unlikely in most livestock situations! There are certain situations where conditions do not favor the raising of goats, sheep, llamas and alpacas. These situations are very rare, but do exist and should be respected. However, don’t automatically assume this situation exists on your farm. It takes a combination of low-lying grazing areas adjoining continuous marshy or swampy areas, frequent rainfall, and an abundance of deer, wet leaves, snails and slugs. This situation is not common and only affects the aforementioned animals. It is very deadly to them if symptoms are not noticed in the early stages and animals are not immediately treated.

The culprit of this rare situation is the meningeal worm, an internal parasite that left unchecked can result in meningitis. While it does not affect cattle or horses, it can be devastating to small ruminants and camelids. Other than the symptoms which become apparent in the later stages of infestation, the only way to prove the meningeal worm is the culprit of sick or dead animals is a necropsy which examines the spinal cord and brain of the expired animal.

While the symptoms of infestation are generally seasonal, they do not become noticeable until late-summer, fall or even early-winter. For all this to begin it takes warm weather, frequent rainfall and an accumulation of leaves. This combination of warm, moist conditions occurs in swampy areas which allow the meningeal worm, snails and slugs to thrive. Then whitetail deer come along and graze in these areas and ingest the worms, snails and slugs. While the deer are hosts to the meningeal worm, it does not affect them. As deer graze, they ingest then expel the worms and eggs which again take a ride on small slugs and snails who roam out into low-lying pastures where small ruminants and camelids graze accidently ingesting a few of the slugs, snails, worms and worm eggs. Once ingested the worm thrives inside the body of these warm animals and lays more eggs. Those eggs hatch out and the infestation and penetration begins.

These internal parasites migrate from the internal organs outward toward the skin and move around, causing the animal to bite or scratch (if they have horns) at their sides, and eventually the parasite makes its way to the spinal cord and then to the brain. As the worm makes contact with the animal’s central nervous system, it causes any number of symptoms which vary from animal to animal. Initially the animal will become unthrifty in appearance, develop a rough coat, develop diarrhea, stop eating, lose weight; which are the same symptoms of gastrointestinal worm infestation. The sick animals tend to keep their distance from other herd members. The symptoms in the progressive stages vary from the animal exhibiting signs of constant pain (after all, the central nervous system is being destroyed by worm larvae), unexplainable limping, continuous tilting of the head, repeated walking in circles, constantly resting its head on fencing or structures, and, in the final stages, pneumonia develops. Between the various complications the animal soon expires.

If caught in the early stages, treatment is possible. But make plans to treat the entire herd to circumvent additional problems. In order to effectively treat animals, a working relationship with a licensed veterinarian is necessary. Treatment is likely to require a combination of off-label wormer and labeled wormer; only a vet can make recommendation for use of an off-label wormer and certain wormers are most effective. I am not a veterinarian (licensed or not) and cannot make any kind of recommendation, nor would I want to out of respect to the profession!! If this is a reoccurring problem, the farmer can conduct deworming treatments on the entire herd of animals in late-summer or fall; while costly, this is more practical than allowing animals to suffer or expire from complications. Again, consult with your local veterinarian!

Sound like a challenge? It is. There really is no preventative treatment for pastures. And killing all the deer in your neighborhood will not terminate the problem. Moving your animals to higher ground may or may not be an option, but the wet, marshy land facilitates the environment that results in this series of complicated matters. To learn much more about this unusual situation visit the websites listed at the end of this article or search the Internet on meningeal worm in goats, sheep, llamas or alpacas. You will learn a whole lot about this rare but deadly situation to small ruminants and camelids. If this situation continues to reoccur on an annual basis, you may want to consider your options for other forms of livestock, poultry, etc. The good news is it does not affect humans.


Robert Spencer is a contributing writer from Florence.