NAVLE Multisystemic

Bovine Vesicular Stomatitis Study Guide

📅 March 28, 2026 ⏱ 25 min read 👁 1 views

Vesicular stomatitis (VS) is a viral disease of livestock caused by vesicular stomatitis virus (VSV), a member of the Rhabdoviridae family.

Overview and Clinical Importance

Vesicular stomatitis (VS) is a viral disease of livestock caused by vesicular stomatitis virus (VSV), a member of the Rhabdoviridae family. It is found only in the Americas and produces vesicular lesions that are clinically indistinguishable from foot-and-mouth disease (FMD), making it a critical differential diagnosis on the NAVLE.

In cattle, VS causes significant economic losses through decreased milk production, weight loss, and secondary mastitis. The disease is reportable and requires immediate notification to state and federal animal health officials.

Serotype	Geographic Range	Clinical Significance
New Jersey (VSV-NJ)	North America, Endemic in Mexico/Central America	Most common serotype in U.S. outbreaks
Indiana (VSV-IND)	South America (subtypes IND-1, IND-2, IND-3)	Less common in cattle, rare in swine

Etiology

Viral Characteristics

Vesicular stomatitis virus (VSV) belongs to the genus Vesiculovirus within the family Rhabdoviridae. The virus is enveloped with a characteristic bullet-shaped virion containing single-stranded, negative-sense RNA.

Serotypes and Geographic Distribution

Vector Family	Examples	Habitat	Transmission
Simuliidae	Black flies (Simulium spp.)	Moving waterways, streams	Biological and mechanical
Psychodidae	Sand flies (Lutzomyia spp.)	Moist areas, organic matter	Transovarial transmission
Ceratopogonidae	Biting midges (Culicoides spp.)	Stagnant water, muddy areas	Mechanical transmission

Epidemiology

Geographic Distribution and Seasonality

VS is endemic in areas from southern Mexico through Central America to northern South America. In the United States, the disease occurs sporadically every 2-10 years, primarily in the southwestern states.

Outbreaks are seasonal, occurring during warm weather months (May through October) and ending with freezing temperatures that kill arthropod vectors.

NAVLE TipRemember VS = Seasonal Southwestern Syndrome. Vesicular stomatitis occurs seasonally in southwestern U.S. states and is the ONLY vesicular disease that affects horses. If you see horses with vesicular lesions, think VS first!

Transmission and Vector Biology

Primary Arthropod Vectors

Transmission Mechanisms

Biological transmission: Virus replicates in arthropod vector, transmitted during subsequent blood feeding
Mechanical transmission: Contaminated mouthparts transfer virus without replication
Direct contact: Contact with vesicular fluid, saliva, or contaminated fomites
Transovarial transmission: Virus passes from infected female sand flies to offspring

Location	Lesion Characteristics	Clinical Impact
Oral mucosa	Vesicles on tongue, lips, gums, dental pad. Quickly rupture to form shallow ulcers	Difficulty eating, excessive salivation
Teats and udder	Vesicles and erosions on teats, may affect udder skin	Secondary mastitis, decreased milk production
Feet/coronary band	Erosions and ulcerations around coronary band and interdigital space	Lameness, reluctance to move

Pathogenesis

VSV enters the host through breaks in the mucosa or skin caused by arthropod bites or minor abrasions. The virus has a tropism for epithelial tissues and replicates locally at the site of inoculation.

Cellular Pathology

Infection begins in the stratum spinosum with ballooning degeneration and intercellular edema leading to vesicle formation. The basal layer of epithelium usually remains intact, allowing for rapid healing.

High-YieldVSV does NOT cause viremia in cattle. The infection remains localized to epithelial surfaces, which is why the disease is generally self-limiting and heals within 10-14 days.

Disease	Horse Susceptibility	Geographic Range	Key Distinguishing Features
Vesicular Stomatitis	SUSCEPTIBLE	Americas only	Horses affected, seasonal pattern
Foot-and-Mouth Disease	RESISTANT	Asia, Africa, Middle East, parts of S. America	Only cloven-hoofed animals

Clinical Signs

Incubation and Course

Incubation period: 2-8 days (average 3-5 days)

Course: Generally self-limiting, resolving in 10-14 days without complications

Primary Clinical Manifestations in Cattle

Early Signs

Fever: 104-106°F (transient, often resolved by time of examination)
Excessive salivation (ptyalism): Often the first sign noticed by owners
Anorexia: Reluctance to eat due to painful oral lesions

Vesicular and Ulcerative Lesions

Economic Impact

Decreased milk production: Can drop 25-50% during acute phase
Weight loss: Due to reluctance to eat
Secondary mastitis: From teat lesions
Trade restrictions: Quarantine and movement restrictions

Sample Type	Collection Method	Storage/Transport
Vesicular fluid	Sterile syringe from intact vesicles	Refrigerate, ship on ice
Epithelial tissue	Epithelial flaps from freshly ruptured vesicles	Glycerol-phosphate buffer or dry ice
Swabs	Polyester swabs from lesions	Viral transport medium
Serum	Acute and convalescent samples (2-3 weeks apart)	Freeze or refrigerate

Differential Diagnosis

The primary differential diagnosis is foot-and-mouth disease (FMD). VS and FMD are clinically indistinguishable in cattle and swine, making laboratory diagnosis essential.

NAVLE TipVS vs. FMD Memory Trick: 'Horses Help Identify VS' - If horses are affected with vesicular disease, it's VS not FMD, because horses are resistant to FMD but susceptible to VS!

Other Differential Diagnoses

Bovine viral diarrhea (BVD): Mucosal disease form, erosive lesions
Malignant catarrhal fever (MCF): Oral erosions, but systemic signs
Bovine papular stomatitis (BPS): Papular rather than vesicular lesions
Bluetongue: Oral lesions plus systemic signs
Chemical burns: History of exposure to caustic substances

Problem	Treatment	Specific Recommendations
Painful oral lesions	Soft feeds, antiseptic mouth washes	Soften hay, provide gruel, dilute iodine solutions
Secondary bacterial infections	Topical or systemic antibiotics	Penicillin, oxytetracycline for severe cases
Teat lesions/mastitis	Gentle milking, mastitis treatment	Intramammary antibiotics, frequent milking
Dehydration	Fluid therapy	IV fluids if animal reluctant to drink
Pain/inflammation	NSAIDs	Flunixin meglumine, phenylbutazone

Diagnosis

Laboratory confirmation is mandatory for all suspected vesicular diseases. Samples must be sent to USDA National Veterinary Services Laboratories (NVSL) or approved National Animal Health Laboratory Network (NAHLN) laboratories.

Sample Collection

Laboratory Tests

Virus Detection

Real-time RT-PCR: Rapid, sensitive detection and serotype identification
Virus isolation: Cell culture on Vero cells or BHK-21 cells
Electron microscopy: Demonstrates characteristic bullet-shaped virions

Serology

Competitive ELISA (cELISA): Antibody detection, long-term immunity
Complement fixation test (CFT): Evidence of recent infection (short-lived titers)
Virus neutralization (VN): Serotype-specific antibodies

High-YieldComplement fixation titers are short-lived and provide the best evidence of recent infection, while cELISA and VN titers persist for years.

Treatment

There is no specific antiviral treatment for vesicular stomatitis. Management focuses on supportive care and prevention of secondary complications.

Supportive Care Protocols

Prevention and Control

Vector Control

Insect control programs: Use of approved insecticides and repellents
Environmental management: Remove standing water, improve drainage
Housing management: Bring animals indoors during peak vector activity
Proximity to water: Avoid pastures near streams, rivers, and wetlands during outbreaks

Biosecurity Measures

Isolation: Separate affected animals immediately
Equipment disinfection: Clean and disinfect shared water troughs, feeders
Personnel protection: PPE when handling affected animals
Movement restrictions: Limit animal movement from affected premises

Vaccination

Currently, there are no approved vaccines for routine use in the United States. Experimental vaccines have been developed but are not commercially available. During outbreaks, killed vaccines may be considered under emergency use authorization.

Regulatory Aspects

Reporting Requirements

Vesicular stomatitis is a reportable disease in the United States. Immediate notification to state and federal animal health officials is required upon suspicion of any vesicular disease.

Quarantine and Movement Restrictions

Premises quarantine: 14-day quarantine after last lesion heals
Movement permits: Required for animal transportation from affected areas
Interstate commerce: Health certificates and testing may be required
International trade: May affect export eligibility for affected states

Zoonotic Considerations

VSV is zoonotic and can infect humans through direct contact with lesions or respiratory exposure. Infection in humans typically causes an influenza-like illness lasting 3-5 days.

Human Clinical Signs

Fever, myalgia, headache: Flu-like symptoms lasting 3-5 days
Vesicular lesions: Rare, may occur on lips, nose, oral cavity
Complications: Encephalitis reported rarely in children

Prevention in Personnel

Personal protective equipment: Gloves, eye protection, masks
Avoid direct contact: With lesions and oral/nasal secretions
Hand hygiene: Thorough handwashing after animal contact

High-YieldAlways wear PPE when examining animals with vesicular lesions. VSV is one of the few livestock viruses that readily infects humans through direct contact.

Prognosis

The prognosis for vesicular stomatitis in cattle is generally excellent. The disease is self-limiting with low mortality (less than 5% in adult cattle) and complete recovery within 10-14 days in most cases.

Recovery Timeline

Days 1-3: Fever, vesicle formation
Days 4-7: Vesicle rupture, ulcer formation
Days 8-14: Epithelial healing, return to normal appetite
Long-term immunity: Protective antibodies persist for 10-12 years

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