Vesicular Stomatitis in Horses and Cattle: Signs, Risks, and What to Do Immediately

By Dr Duncan Houston

Vesicular stomatitis is one of the few diseases that can trigger immediate concern at both farm and regulatory level. Not because it is usually fatal, but because it looks very similar to foot-and-mouth disease. That similarity alone can lead to movement restrictions, quarantine, and major economic disruption.

The other challenge is that vesicular stomatitis spreads quietly through vectors like flies and through routine handling, meaning outbreaks can escalate before they are fully recognised.

This guide explains what vesicular stomatitis actually is, how to recognise it early, how it spreads, and what to do immediately to protect your animals, your staff, and your operation.

Quick Answer

Vesicular stomatitis is a viral disease affecting horses and cattle that causes blister-like lesions on the mouth, teats, and feet. It spreads through biting flies, direct contact, and contaminated equipment, and can also infect humans. Because it mimics foot-and-mouth disease, any suspected case must be reported immediately. Isolate affected animals, implement strict biosecurity, and involve a veterinarian without delay.

Why Vesicular Stomatitis Matters

The disease itself is usually self-limiting, but the consequences can be significant.

It matters because:

• It mimics foot-and-mouth disease

• It is reportable and triggers regulatory action

• It spreads easily in warm conditions

• It affects animal welfare and productivity

• It poses a zoonotic risk to humans

Clinical Insight

The biggest risk is not the virus alone. It is the response required once a suspicious case is identified. Early recognition and correct action protect both the herd and the operation.

What Is Vesicular Stomatitis?

Vesicular stomatitis is caused by a virus that leads to blister formation in:

• Mouth and lips

• Tongue

• Teats and udder

• Coronary bands and feet

These blisters can rupture, leaving painful ulcers.

What It Looks Like in the Real World

Signs typically appear within several days after exposure.

Early Signs

• Drooling

• Reduced appetite

• Mild fever

• Reluctance to eat or move

More Advanced Signs

• Blisters or ulcers in the mouth

• Excess salivation

• Lameness due to foot lesions

• Teat lesions affecting nursing or milking

Decision Checkpoint

Any blistering disease affecting the mouth or feet should be treated as a potential regulatory issue until proven otherwise.

Severity Framework: How Serious Is It?

Mild

• Small lesions

• Mild discomfort

• Normal behaviour otherwise

Monitor closely and isolate.

Moderate

• Multiple lesions

• Reduced intake

• Mild lameness

Requires veterinary involvement and strict isolation.

High Risk

• Widespread lesions

• Significant lameness

• Reduced production

• Multiple animals affected

Immediate biosecurity measures required.

Critical

• Rapid spread

• Severe production impact

• Regulatory involvement

Urgent containment and reporting required.

Why It Spreads So Easily

Primary Transmission Routes

• Biting flies (major driver)

• Direct contact with infected animals

• Contaminated equipment and surfaces

• Handling of lesions

Environmental Factors

• Warm temperatures

• High fly populations

• Standing water

• Increased animal movement

Clinical Insight

Most outbreaks are seasonal and linked to vector activity. Fly control is one of the most important preventive measures.

Zoonotic Risk: What About Humans?

Humans can become infected through:

• Contact with lesions

• Handling infected animals

• Exposure to contaminated fluids

Typical human signs:

• Fever

• Fatigue

• Muscle aches

Decision Checkpoint

Anyone handling suspected cases should use protective equipment and monitor for symptoms.

Diagnosis: Why It Must Be Confirmed Properly

Because vesicular stomatitis mimics foot-and-mouth disease, diagnosis must be confirmed through:

• Laboratory testing

• PCR analysis of lesion samples

• Official reporting pathways

Critical Point

Do not attempt to manage suspected cases quietly. Immediate reporting is required.

What to Do Immediately If You Suspect It

1. Isolate the affected animal

2. Stop movement of animals on and off the property

3. Contact your veterinarian immediately

4. Notify appropriate authorities if required

5. Avoid handling lesions without protection

6. Begin strict hygiene and biosecurity protocols

Time-Based Guidance

• Suspected case: act immediately

• Confirmed case: enforce strict quarantine

• Post-case: monitor for at least 14 days after last signs

Quarantine and Biosecurity

Once confirmed or suspected:

• No animal movement without approval

• Dedicated equipment for affected animals

• Strict cleaning and disinfection

• Controlled access to facilities

• Ongoing monitoring of all animals

Supportive Treatment: What Helps Recovery

There is no direct cure for the virus.

Management focuses on:

• Pain relief using anti-inflammatories

• Soft, palatable feed

• Clean water

• Minimising stress

• Treating secondary infections if needed

Clinical Insight

Most animals recover within 1 to 2 weeks, but discomfort can be significant and production losses can occur.

Prevention: What Actually Reduces Risk

Fly Control

• Insecticides

• Fly traps

• Fans in housing

• Removal of standing water

Hygiene and Equipment Control

• Disinfect tools regularly

• Avoid sharing equipment between groups

• Clean clothing and boots

Monitoring

• Daily checks during high-risk seasons

• Early identification of lesions

• Rapid isolation

Decision Checkpoint

If your system does not include active fly control and biosecurity during warm months, risk is significantly higher.

Common Mistakes

• Ignoring early lesions

• Delaying reporting

• Allowing continued animal movement

• Poor fly control

• Sharing equipment between groups

• Underestimating zoonotic risk

Economic Impact

Even mild outbreaks can result in:

• Movement restrictions

• Reduced production

• Increased labour

• Veterinary costs

• Trade limitations

Clinical Insight

The biggest cost often comes from restrictions, not mortality.

FAQs

Is vesicular stomatitis fatal?

Rarely, but it can cause significant welfare and production issues.

Why is it taken so seriously?

Because it resembles foot-and-mouth disease.

How does it spread most commonly?

Through biting flies and contaminated equipment.

Can humans get it?

Yes, but usually mild flu-like illness.

How long does recovery take?

Typically 7 to 14 days.

Final Thoughts

Vesicular stomatitis is a manageable disease, but only when it is taken seriously from the start.

The key factors are:

• early recognition

• immediate isolation

• strict biosecurity

• correct reporting

• consistent monitoring

Most problems arise from delay, not difficulty.

The earlier you act, the easier it is to contain.

If you want help setting up biosecurity protocols, managing suspected cases, or protecting your herd during high-risk seasons, ASK A VET™ can support fast, practical decision-making when it matters most.