Biosecurity crucial in keeping vesicular stomatitis at bay in US

The tongue of a horse with vesicular stomatitis.
The tongue of a horse with vesicular stomatitis.

Horses owners in affected parts of the United States are being urged to guard against the potential spread of vesicular stomatitis, with cases affecting three states so far.

The first case was identified in mid-April in New Mexico, much earlier than normal as the viral disease typically occurs during summer and into fall. Further cases have since been identified in New Mexico, as well as in Arizona and Texas.

In some years, the disease does not occur at all.

Vesicular stomatitis is a contagious, viral disease that, while rarely life-threatening, can have a big financial impact on individual horse owners and the state’s equine industry, says Dr Barry Whitworth, a veterinarian with Oklahoma State University’s Extension.

It is a reportable disease. State and federal animal health authorities will be contacted by a horse owner’s local veterinarian and the state veterinarian will quarantine an affected farm or ranch if a case is confirmed through testing, Whitworth says.

During outbreaks, equestrian event organizers may choose to cancel shows, rodeos and similar events in the surrounding area. Interstate horse movements may also be restricted.

Symptoms include blister-like lesions on the tongue, mouth lining, nose or lips of an affected horse.

Excessive salivation, difficulty in eating and swelling of the coronary band also may be seen.

In some cases, lesions develop on a horse’s udder or sheath.

Whitworth advises horse caregivers to contact their veterinarian immediately if such symptoms are seen.

The disease can be passed from horse to horse by contact with saliva or fluid from ruptured blisters.

“Insect control programs should be implemented as insects are the primary manner in which the virus is spread,” says Kris Hiney, an equine specialist with the Extension.

“Physical contact between animals, or contact with buckets, equipment, housing, trailers, feed, bedding, shared water troughs or other items used by an infected horse also can provide a ready means of spread.”

University experts have a range of suggestions to help prevent the disease:

  • Healthy horses are more disease resistant, so provide good nutrition, regular exercise, deworming and routine vaccinations;
  • Isolate new horses for at least 21 days before introducing them into a herd or stable;
  • Implement an effective insect-control program as certain types of flies and midges can transmit the disease. Remove manure promptly and eliminate potential breeding grounds for insects such as standing water and muddy areas;
  • Use individual rather than communal feeders, waterers and equipment;
  • Clean and disinfect feed bunks, waterers, horse trailers and other equipment regularly;
  • Be sure farriers and other equine professionals who come into direct contact with the horse exercise caution so as not to spread the disease from one horse or facility to the next.

For facilities where vesicular stomatitis has been confirmed, horses with lesions should be isolated from others.

Healthy animals should always be handled first and ill animals handled last. Handlers should then shower, change clothing and disinfect equipment to prevent exposing others.

Anyone handling infected horses should implement proper biosafety methods including wearing latex gloves and washing hands after handling animals with lesions.

“If you’re sponsoring an equine event during an outbreak, require a recent health certificate on every horse entering the location and consider having a veterinarian visually inspect all horses at check-in,” Hiney said.

“Work with the veterinarian to establish isolation and response procedures that can be implemented quickly if a suspected case is identified at the site.”

Vesicular stomatitis can also be transmitted from infected horses to humans. The disease in humans tends to cause severe flu-like symptoms such as headache, fever, muscle aches and extreme fatigue.

Whitworth and Hiney say anyone who experiences flu-like symptoms after working with an infected horse should contact a doctor immediately.

The US Department of Agriculture and Equine Disease Communication Center have resources online about the disease.

Latest research and information from the horse world.

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