What Is EHV-1?

Equine Herpesvirus-1 is a contagious virus that affects respiratory, neurological, and reproductive systems. Many horses carry it silently. Stress, travel, herd changes, and immune challenges can trigger shedding.

How EHV-1 Spreads

• Direct horse-to-horse contact
• Respiratory droplets
• Shared buckets, tack, grooming tools, hoses
• Contaminated hands, clothing, and equipment
• People moving between barns or events

Symptoms

Respiratory Form

• Fever
• Cough
• Nasal discharge
• Reduced energy and appetite

Neurological Form (EHM)

• Hind-end weakness
• Incoordination or stumbling
• Dog-sitting posture
• Difficulty walking or standing

Reproductive Form

Can lead to late-term abortion or weak foals in pregnant mares.

Infection Timeline

Incubation period is typically 2–10 days. Horses may shed virus before obvious symptoms. Fever is often the earliest sign, which is why temperature logs are so valuable.

Prevention Protocols

• Record temperatures twice daily for all horses
• Quarantine new arrivals for 14–21 days
• Stop sharing buckets, grooming tools, and tack
• Disinfect trailers, partition walls, and ties after travel
• Reduce stress with adequate rest, hydration, and turnout
• Follow veterinarian-guided vaccination programs

Outbreak Response

• Isolate any horse with fever or suspicious signs immediately
• Implement barn-wide temperature monitoring
• Limit barn access to essential caretakers only
• Disinfect high-touch surfaces several times per day
• Work closely with your veterinarian on testing and timelines

Effective Disinfection

Disinfectants proven effective against EHV-1 include:

• Accelerated hydrogen peroxide
• Properly diluted bleach solution
• Quaternary ammonium compounds
• Potassium peroxymonosulfate products

Always follow label directions for dilution and contact time.

Travel & Show Safety

• Bring your own buckets, hoses, and halters
• Avoid nose-to-nose contact with unfamiliar horses
• Wash or sanitize hands before handling different horses
• Avoid shared wash racks or tie rails when possible
• Space horses apart in trailers and at tie areas

Common Myths

• “Only sick horses spread it.” Healthy-looking carriers can shed virus.
• “Vaccinated horses can’t get it.” Vaccines reduce severity, not all risk.
• “Small barns are automatically safer.” Movement in and out still matters.
• “Direct contact is the only risk.” Contaminated tools and surfaces are big factors.

Comprehensive EHV-1 FAQ

1. How serious is EHV-1 for horses?

EHV-1 can cause mild respiratory illness, neurological disease, or reproductive loss. Most horses recover, but outbreaks require strict biosecurity and movement control.

2. How long does EHV-1 incubation take?

The incubation period is typically 2–10 days. Horses may begin shedding virus before outward symptoms appear.

3. What is the first symptom most barns miss?

Fever is often the earliest sign of EHV-1. That is why twice-daily temperature logs are such an effective early-warning system.

4. Can vaccinated horses still get EHV-1?

Yes. Vaccination reduces the severity of disease and viral shedding, but it does not fully eliminate the possibility of infection.

5. How does EHV-1 typically spread between horses?

EHV-1 spreads through respiratory droplets, shared equipment and tools, contaminated hands, tack, water sources, and surfaces in barns and trailers.

6. Can horses carry EHV-1 without showing symptoms?

Yes. Some horses can carry EHV-1 in a latent state and shed virus unexpectedly, which is why biosecurity matters even when all horses look healthy.

7. How long can EHV-1 survive on surfaces?

EHV-1 can survive for hours to days on surfaces depending on temperature, humidity, and organic debris. Regular disinfection is essential in high-risk periods.

8. Which disinfectants are effective against EHV-1?

Accelerated hydrogen peroxide, properly diluted bleach solutions, quaternary ammonium compounds, and potassium peroxymonosulfate products are considered effective when used as directed.

9. When should a horse be isolated for possible EHV-1?

Any horse with an unexplained fever, respiratory signs, or neurological changes should be isolated immediately until your veterinarian can evaluate the situation.

10. How long should new horses be quarantined?

Most barns follow a 14–21 day quarantine for new arrivals, using separate tools, water sources, and turnout during that period.

11. Does EHV-1 pose special risks for pregnant mares?

Yes. EHV-1 is associated with late-term abortion and weak foals, so pregnant mares should follow stricter isolation and monitoring protocols in high-risk periods.

12. What increases EHV-1 risk during travel?

Shared stalls, crowded warm-up pens, common wash racks, nose-to-nose contact, and contaminated tie areas all increase exposure risk during travel and shows.

13. Can horses recover fully from neurological EHM?

Some horses recover fully from neurological signs, while others may have lasting deficits. Early identification, isolation, and veterinary-guided care can improve outcomes.

14. Why are temperature logs so important?

Temperature logs catch early fever before other symptoms appear, giving barns a chance to isolate and act quickly before the virus spreads.

15. When is it safe to lift quarantine after an outbreak?

Quarantine should only be lifted under veterinary guidance, based on negative testing, the expected duration of viral shedding, and barn-wide monitoring.