COVID-19 in Horses by a Vet – 2025 Insight on Risk, Testing & Transmission 🦠🐴

By Dr Duncan Houston, BVSc

Introduction

While COVID-19 (caused by SARS-CoV-2) has primarily impacted humans and some companion animals, recent veterinary research shows that horses can contract and carry the virus asymptomatically. Although they do not currently become clinically ill, the concern remains that they could potentially serve as silent carriers—especially in environments with active human outbreaks. This 2025 vet-reviewed guide explores what we know about COVID-19 in horses, based on ongoing research from UC Davis and national surveillance efforts.

Key Findings So Far 📊

• Horses appear susceptible to COVID-19, but show no signs of illness
• They may play a role in silent transmission, particularly in close-contact barns or racetracks
• Human-to-horse transmission has been documented in low but measurable rates
• Viral material was detected in nasal secretions of healthy horses through PCR testing

Research Summary 🧪

UC Davis & Del Mar Study Highlights:

• 667 horses with respiratory signs were tested from 2019 to 2020—none tested positive for COVID-19
• 587 healthy horses at Del Mar racetrack—6% tested positive for SARS-CoV-2
• 1100 horses evaluated at UC Davis—3.5% tested positive

Most positive horses were healthy racehorses and had no clinical signs, suggesting the virus was likely acquired from human exposure rather than horse-to-horse spread.

How Do Horses Get COVID-19? 🧬

• Likely source: Human handlers or barn staff with or without symptoms
• Transmission route: Aerosolized particles, contaminated hands or surfaces
• Spike protein receptors in horses resemble human receptors, making infection possible

What’s the Risk in 2025? 📉

• There are no confirmed cases of horses developing respiratory illness from COVID-19
• No horse-to-human transmission has been documented
• Risk is low—but future mutations of the virus could increase host range
• Veterinarians and researchers continue to monitor for potential cross-species adaptation

Why We Still Test 🧪

Even if horses are not clinically sick, testing matters for public health and disease tracking:

• Monitor virus movement through barn environments
• Prevent unexpected adaptation or mutation in multi-species barns
• Protect staff and visitors who may be immunocompromised

Veterinary Recommendations in 2025 🩺

• Don’t panic: Horses are not known COVID-19 spreaders
• Isolate symptomatic people—even if horses appear healthy
• Continue good barn hygiene: hand washing, clean tools, masks if an outbreak occurs
• No vaccine for horses is currently needed or available
• Consider testing in barns with known human outbreaks

When to Be Cautious 🚨

• Large training barns, racetracks, or show barns with shared personnel
• Multi-species facilities (e.g., horses, dogs, cats in proximity)
• Human COVID-19 outbreaks in staff or handlers

Signs to Watch (Even Though Rare) 👀

Though not seen in current research, veterinarians still recommend monitoring for:

• Fever or elevated temperature
• Unusual nasal discharge
• Unexplained coughing or breathing difficulty
• Lethargy in healthy horses after known human exposure

Case Example: Stable Exposure

1. A groom tested positive for COVID-19 at a California racetrack in 2020
2. Several horses in contact tested positive via PCR despite no symptoms
3. Horses remained in light isolation with increased biosecurity
4. No clinical illness developed; testing helped track environmental exposure

FAQs About COVID-19 in Horses

Q: Can horses get sick from COVID-19?

A: Not at this time. Studies show asymptomatic carriage but no confirmed illness.

Q: Can horses transmit COVID-19 back to humans?

A: This has not been proven. Risk is theoretical and being monitored closely.

Q: Should I keep COVID-positive people away from horses?

A: Yes—out of caution and to limit viral circulation in any species.

Conclusion

Horses are not at high risk from COVID-19, but they are susceptible to asymptomatic infection. As of 2025, there’s no evidence of illness or interspecies transmission—but ongoing monitoring and barn biosecurity remain important. Whether you manage a backyard horse or a professional string, stay informed, practice hygiene, and communicate with your vet during any human outbreaks in the barn.

Have questions about COVID-19 and your horses? Contact Ask A Vet via AskAVet.com or our app 📱 to get up-to-date advice from Dr Duncan Houston and our equine health team. 🩺🐴