Neurological Problems in Horses by a Vet – 2025 Guide to EPM, Wobblers & Herpes Virus 🧠🐴

By Dr Duncan Houston, BVSc

Introduction

Horses can suffer from a variety of neurological diseases—conditions that affect their brain, spinal cord, or nerves. In 2025, the most commonly encountered include Equine Protozoal Myelitis (EPM), Wobbler Syndrome, and Equine Herpesvirus-1 (EHV-1). Each of these conditions causes signs like incoordination, weakness, or muscle atrophy, and each requires fast, accurate diagnosis and tailored treatment.

1. Equine Protozoal Myelitis (EPM) 🧬

Cause

• Caused by the protozoa Sarcocystis neurona
• Transmitted via opossum feces in contaminated feed, water, or pasture

Signs of EPM

• Asymmetrical muscle loss
• Stumbling or uncoordinated gait (ataxia)
• Head tilt or facial nerve paralysis
• Behavioral changes or weakness

Diagnosis Challenges

• Blood tests show exposure but not active disease
• Spinal fluid testing is more accurate but invasive
• Often overdiagnosed due to vague symptoms

Prognosis & Treatment

• Early treatment can help—but some horses retain deficits
• Anti-protozoal drugs, anti-inflammatories, and supportive care are used

2. Wobbler Syndrome (Cervical Vertebral Stenotic Myelopathy) 🦴

Cause

• Narrowing of cervical (neck) vertebrae causes spinal cord compression
• Can be developmental (young horses) or degenerative (older horses)

Symptoms

• Wobbling in hind limbs
• Knuckling over or stumbling
• Symmetrical incoordination (vs EPM’s asymmetry)

Diagnosis

• Neck x-rays or myelogram (dye contrast test) confirm narrowing

Treatment & Prognosis

• Surgical correction possible in some cases (basket surgery)
• Mild cases may be managed with restricted exercise

3. Equine Herpesvirus-1 (EHV-1) Neurologic Form 🦠

Cause

• Contagious virus spread by respiratory contact
• Stress and travel often trigger outbreaks

Symptoms

• Weakness or paralysis of hind legs
• Loss of tail tone or bladder control
• Fever and nasal discharge may precede signs

Diagnosis & Outbreak Response

• PCR nasal swab confirms viral presence
• Highly contagious—quarantine and testing required

Treatment

• Supportive care and anti-inflammatories
• Some horses recover, others remain disabled

Other Neurological Diseases to Watch For ⚠️

Rabies

• Rare but fatal—transmitted through wildlife bites
• Signs include aggression, ataxia, and inability to swallow
• Vaccination is essential

West Nile Virus

• Mosquito-borne virus that affects the brain and spinal cord
• Can cause muscle twitching, weakness, and seizures
• Vaccination and mosquito control are preventive tools

When to Call Your Vet 📞

• Wobbling or stumbling
• Loss of balance or muscle weakness
• Behavior changes or inability to rise
• Sudden fever with hind limb weakness

FAQs About Equine Neurological Diseases

Q: Can horses recover from EPM?

A: Some do, especially with early treatment, but others may retain lasting neurological deficits.

Q: How do I tell EPM from Wobblers?

A: EPM usually affects one side more than the other; Wobblers tends to be symmetrical. Imaging helps confirm.

Q: Can EHV-1 be prevented?

A: Vaccines reduce shedding but don’t prevent the neurological form. Biosecurity and isolation are critical.

Conclusion

Neurological diseases in horses are serious, often urgent medical conditions. Whether it’s EPM from opossum exposure, spinal compression from Wobblers, or viral paralysis from EHV-1, early veterinary diagnosis and treatment can make a critical difference. Monitor for signs like unsteady gait, sudden weakness, or behavioral changes, and seek help immediately.

Need help evaluating strange symptoms in your horse? Visit AskAVet.com or download our app 📱 to consult with Dr Duncan Houston for advanced neurological diagnostics. 🩺🐴