epm in horses

EPM In Horses

Last Updated on September 1, 2020

EPM in horses is a serious disease and requires early detection for a horse to improve and survive.

In this article you will learn the signs you must know in order to detect Equine Protozoal Myeloencephalitis before it is too late.

With early diagnosis and treatment, a horse can make a recovery and live with a better quality of life.

You will also learn how your vet will diagnose and treat this potentially fatal disease along with essential tips you can implement to prevent a horse from contracting EPM.

What is EPM in Horses

EPM in horses is a neurological disease that is caused by a parasite, or protozoa. 

The parasite that causes this disease is known as Sarcocystis Neurona. It will attach to the horse’s brain and the spinal cord, seriously harming the central nervous system.

Here is an excellent video description of EPM, also known as Equine Protozoal Myeloencephalitis, and it’s effects

The full name for this potentially life-threatening condition is Equine Protozoal Myeloencephalitis.

EPM is a condition that can be treated as long as it has been detected in time.

The problem with this disease is that the signs of EPM can be difficult to identify early on.

Signs and symptoms of EPM aren’t always easy to determine.

The medical community understands the symptoms of EPM, but many of these symptoms are also associated with other afflictions.

This means that a horse owner needs to be diligent in order to determine what is going on in time.

What are the Symptoms of EPM?

  • Head tilting
  • Poor balance
  • Splay legged stance
  • Difficulty swallowing
  • Loss of coordination
  • Weakness
  • Head and face paralysis
  • Seizures
  • Lameness or unusual gait
  • Stiff or slow movement
  • Muscle atrophy

here are many different symptoms that are associated with EPM

One of the first signs owners notice is a lack of coordination.

Horses may exhibit stumbling, awkward movements and changes in their gait.

General ataxia and moving stiffly are potential signs that a horse may have EPM.

Owners may also notice their horse appears much weaker than usual.

Horses with EPM often have difficulty maneuvering inclines and declines in terrain.

Muscle atrophy is not uncommon in EPM cases, occurring most often in the hindquarters and topline.

The muscle in the face is often effected as well.

This is characterized by a drooping lip and eyes.

Other horse EPM symptoms include difficulty swallowing, a loss of sensation in the face or other areas of the body, and a horse needing to lean on walls for support.

Abnormal sweating will sometimes occur in horses suffering from EPM.

Seizures, while somewhat rare, can accompany EPM.

More symptoms will present themselves as the condition progresses.

Symptoms may only be subtle at first, so catching this disease early on will take a very attentive owner.

Owners that are very aware of their horse’s normal behavior patterns may recognize when something seems a bit off.

It isn’t necessarily easy to spot these subtle symptoms right away, though. A horse being a little off balance may not always be apparent, especially if you aren’t riding the horse regularly. 

If you suspect that anything is off about your horse or if you notice any symptoms, it is crucial that you call your veterinarian as soon as possible.

What Causes EPM and How Does a Horse Get it?

epm lifecycle

Horses get this disease by ingesting these parasites.

There are various ways that a horse can be infected with this type of parasite. One of the most common ways is by coming into contact with opossum feces on their food or water.

Opossums seem to be the most common host for the Sarcocystis neurona parasite.

If a horse ingests feed that has been tainted by possum feces, then they will be prone to contracting EPM.

Horse owners will want to do their best to keep opossums away from their horse stables and pasture in order to prevent this from happening.

Once a horse has contracted EPM, they will not be able to pass it to another horse.

This means that you do not need to worry about other horses in your stable catching the parasite from an already infected horse.

They will be able to interact as normal without the chance of spreading the disease.

There are certain factors that will make a horse more susceptible to getting EPM.

Horses that are younger than five years old tend to be more prone to contracting EPM.

Horses that are older than thirteen years old also have an increased risk.

Greater risk for EPM additionally occurs in horses with compromised immune systems.

Certain diseases can compromise an immune system, but so can stress.

If a horse’s immune system is chronically stressed, then they will be more likely to develop EPM when exposed to the parasite.

With this in mind, maintaining top overall equine health is one of the best ways to prevent this potentially devastating disease.

EPM Diagnosis

Due to the potential progression of this disease, early diagnosis is critical to the chances of successful treatment.

Delayed diagnosis can leave owners with few avenues for a successful outcome.

The earliest treatments seem to be the most effective when it comes to this disease.

Getting your horse properly diagnosed will require a skilled equine veterinarian.

Diagnosis can prevent some difficulties because of many of the symptoms of EPM mirroring those of other conditions.

Even so, your veterinarian should be able to come to the proper conclusion after a thorough examination.

In this video you can see an overview of a veterinarian assessment for neurological diseases and the importance for early diagnosis.

Typically, a veterinarian will start with a comprehensive physical examination of the horse.

This will allow the veterinarian to assess the overall health of the horse and they can determine any issues that are present.

EPM often tends to impact one side of the horse’s body more than the other, so this can be an important facet of diagnosing the condition properly.

The veterinarian will likely want to draw some blood from your horse to have it examined.

They will also consider testing the spinal fluid of the horse in order to come to an ultimate conclusion.

Once the tests have been run, they should know definitively whether or not your horse has EPM.

Treatment EPM

Treating this condition is possible as long as it was caught in time.

Treatments have the greatest chance of being successful when they are administered during the early stages of the disease.

A high percentage of these early diagnosis cases showcase significant improvements once treatments have been given.

It is even possible for the symptoms of EPM to be completely reversed. 

This is excellent news for horse owners and should give hope to any who are suspecting that their horse may be suffering with EPM.

There are many different medications and treatment options to consider when your horse has developed EPM.

Anti-inflammatory drugs can be excellent for helping a horse manage their pain.

There are anti-protozoal drugs on the market that can treat the cause of EPM quite effectively.

Some of these treatments are quite expensive, but they are effective.

Supplements may also be given to your horse to improve its overall health.

When they are on the EPM medication, they will need to be observed closely in order to ensure that the medication is having the intended effects.

It can be a taxing process, but the success rate of treatments should give horse owners confidence to follow through.

Some of these treatments can negatively impact the fertility of stallions.

It can also come with health risks to unborn foals. These problems aren’t common, but they are something to be aware of.

A small percentage of horses who go through these treatments may relapse.

Some horses won’t respond to the treatments as well as others. At this point it is unknown exactly why some horses respond well to treatment while others do not.

It isn’t always guaranteed that things will work out successfully, but chances of success are always increased when treatment is started early.

EPM Prevention Advice

Of course, preventing EPM from ever impacting your horse is the best outcome.

Owners will need to keep their horse from coming in contact with infected feces.

There are some preventative measures that you can take to limit the likelihood of them coming into contact with the parasite.

Keeping your feed properly sealed is a great way to prevent it from becoming contaminated.

Keeping the all rooms where the horses feed is stored should be sealed to prevent infected animals from entering.

Doing your best to prevent rodents of any kind from getting into the feed is going to lessen the chances of contamination.

Feeding a horse on the ground should be avoided at all times, as this will make it more likely for them to come into contact with a parasite when eating off the ground. 

Set up proper feeding areas for your horses that you can keep clean and controlled.

You should take steps to ensure that the water source that your horses are using is as clean as possible at all times.

If you ever notice any dead animals on your property, dispose of the carcass right away.

You don’t want to allow any parasites to fester.

Carcasses will draw scavengers to the property, and you will have more potentially contaminated feces to deal with.

Do your best to maintain a healthy lifestyle for your horse.

Feed your horse a properly balanced diet, and make sure that the horse gets plenty of exercise.

This will keep the immune system of the horse as healthy as possible and will protect it from the disease.

For more essential equine health tips check out these articles


EPM can be scary but with early detection and proper treatment improvements can be attained. 

It is imperative that all horse owners know the symptoms and be aware of any signs of EPM in their horse.

Early detection is the key and treatment must not be delayed.

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