How to Diagnose EPM in Horses? Common Signs and Treatment Solutions

Equine Protozoal Myeloencephalitis (EPM) is a serious neurological condition affecting horses of any age or breed. 

Protozoal parasites, being the primary cause, can impact the central nervous system and lead to many other symptoms. 

It is crucial to detect EPM early, as leaving it untreated can cause permanent harm to the nervous system or even death.

This blog will discuss the following in detail:

• What Is EPM In Horses

• What actually causes the dangerous conditions in horses?

• Signs of EPM (Equine Protozoal Myeloencephalitis) in Horses 

• Common Tests for Diagnosing EPM in Horses?

• Progression and Long-Term Effects

• Standard Treatment Options for EPM condition in horses

• Can EPM in Horses Be Cured?

• Preventing the EPM disorder in Horses

• DVM Central: Your Partner in Equine Health

What Is EPM In Horses

It is a serious neurological condition that affects horses of any age or breed. Protozoal parasites are the primary cause of the condition, which can impact the central nervous system and lead to many other symptoms.

What Causes EPM in Horses?

Protozoal parasites are considered the leading cause of EPM disease in horses and fatally affect the central nervous system. 

However, there are other causes that can also trigger the disease:  

• Parasite Sarcocystis neurona responsible for EPM.
• Horses ingest parasites through contaminated feed or water.
• Opossum feces are the main source of contamination.
• Poor feed storage allows parasites to spread.
• Stress or weak immunity makes horses more vulnerable to infection.
• Grazing in areas frequented by opossums increases the risk.
• Exposure to wildlife in unsanitary conditions can lead to infection.
• Horses living in endemic regions are at higher risk of contracting EPM.

What Are the First Signs of EPM in Horses?

Early detection is key to managing EPM. The first signs of Equine Protozoal Myeloencephalitis in horses can be subtle and vary widely, but common indicators include: 

• Weakness: 

One side of the body may appear weaker than the other.

• Ataxia (uncoordinated movements): 

Difficulty walking or maintaining balance.

• Muscle wasting: 

Especially noticeable in the face or along the topline.

• Head tilt: 

A visible tilt to one side.

• Difficulty swallowing: 

Some horses may struggle with eating or drinking.

• Behavioral changes: 

Lethargy, depression, or unusual aggression.

Keep a close eye on these symptoms, as they can worsen over time without intervention.

How to Test for EPM in Horses

EPM diagnosis in horses is complex and involves following several steps coordinated by a veterinarian. This ensures correct disease diagnosis and enables one to avoid some treatment that will never work. 

It covers clinical assessment, higher-level laboratory analysis, and differential diagnosing.

1. Clinical Examination

The veterinarians initially conduct a physical and neurologic examination to determine the abnormality in a horse's health.

• Look for ataxia and muscle weakness.
• Check reflex responses and gait.
• Observe facial asymmetry or head tilt.
• Evaluate swallowing difficulties.
• Identify behavioral or mood changes.

2. Blood and CSF Testing

Blood and cerebrospinal fluid (CSF) testing are critical in confirming exposure to Sarcocystis neurona. These tests detect the presence of antibodies to the parasite.

• Perform a blood sample analysis.
• Test CSF for antibodies.
• Rule out false positives.
• Compare antibody levels in blood and CSF.
• Use immunodiagnostic tools for accuracy.

3. Rule Out Other Diseases

EPM symptoms often mimic other neurological conditions. Therefore, ruling out alternative diagnoses is essential for a definitive conclusion.

• Test for West Nile Virus.
• Check for Lyme disease symptoms.
• Examine for cervical vertebral stenotic myelopathy (wobbler syndrome).
• Consider spinal trauma as a factor.
• Rule out rabies or other infections.

Signs of EPM in Horses: Progression and Long-Term Effects

EPM can have varying effects depending on the severity and timing of treatment. Left untreated, the condition can lead to:

• Severe muscle atrophy
• Paralysis
• Permanent neurological deficits
• Behavioral changes that affect performance or temperament

Early treatment significantly reduces the risk of long-term damage.

Treatment for EPM in Horses

The management of EPM involves eliminating the parasite, decreasing inflammation, and supporting neurological recovery. Such treatments as medication, together with caregiving and rehabilitation, play a crucial role in improving outcomes.

1. Antiprotozoal Medications

These drugs target and eliminate the protozoa causing EPM, stopping disease progression and aiding recovery.

• Administer ponazuril or diclazuril.
• Use sulfadiazine-pyrimethamine if required.
• Follow prescribed dosages carefully.
• Begin treatment immediately after diagnosis.
• Monitor for side effects during therapy.

2. Supportive Care

Supportive treatments help reduce inflammation and support neurological recovery during and after medication.

• Provide anti-inflammatory medications.
• Supplement with Vitamin E for nerve health.
• Offer antioxidants to reduce oxidative stress.
• Manage pain using appropriate drugs.
• Boost immunity with additional therapies.

3. Physical Rehabilitation

Physical rehabilitation is essential to restore strength, balance, and coordination in affected horses.

• Develop a customized exercise plan.
• Focus on improving strength gradually.
• Use massage therapy to relieve stiffness.
• Incorporate chiropractic or physiotherapy sessions.
• Prevent further muscle wasting through regular movement.

4. Ongoing Monitoring

Continuous monitoring ensures the effectiveness of treatment and minimizes the risk of relapse.

• Schedule follow-up veterinary visits.
• Track improvements in neurological symptoms.
• Adjust medication or therapies as needed.
• Watch for recurring signs of EPM.
• Maintain a detailed health record for reference.

5. Environmental Management

Preventing re-exposure is a critical part of long-term recovery. Effective management reduces the likelihood of reinfection.

• Eliminate opossum access to feed and water.
• Store feed in sealed containers.
• Clean contaminated pastures regularly.
• Reduce stress to improve immunity.
• Educate handlers about EPM prevention strategies.

Can EPM in Horses Be Cured?

With timely diagnosis and treatment, many horses recover from EPM. However, full recovery depends on:

• How quickly treatment begins
• The severity of neurological damage
• The overall health and age of the horse

While some horses regain full function, others may experience residual effects, requiring long-term care or adjustments in their routine.

Is EPM Contagious in Horses?

No, EPM is not contagious between horses. The disease is caused by environmental exposure to parasites, not direct horse-to-horse contact. 

However, managing your horse’s environment is essential to reduce the risk of infection.

Preventing EPM in Horses

Prevention is better than cure. Here are steps to minimize the risk of EPM:

• Control Wildlife Access

Keep opossums and other wildlife away from feed and water sources.

• Maintain Clean Pastures

Regularly inspect pastures for contamination.

• Store Feed Properly

Use sealed containers to prevent contamination from feces.

• Monitor Horses Closely

Be vigilant for early signs of illness, especially in high-risk areas.

DVM Central: Your Partner in Equine Health

When it comes to managing EPM in horses, knowledge and resources make all the difference. 

DVM Central is a leading veterinary marketplace where you can buy quality animal health-related products and address common disease concerns. 

Additionally, we conduct RACE-approved Virtual Expos to help veterinary professionals stay current with trends and elevate their practices. 

Visit our veterinary marketplace for your needs, where you can get discounted veterinary supplies and join a community dedicated to equine wellness. 

FAQs

 

What Are the Long-Term Effects of EPM?

The severity of the disease determines the long-term effects. Untreated cases may result in permanent neurological deficits, muscle atrophy, or behavioral changes.

How Long Does Treatment for EPM In Horses Take?

Treatment duration varies, typically lasting several weeks to months. Regular veterinary follow-ups are essential to assess progress.

Can Equine Protozoal Myeloencephalitis in Horses Reoccur?

Yes, EPM can reoccur if the immune system weakens or the horse is re-exposed to the parasite. Vigilant management is crucial.