Nearly 400 horses hit in vesicular stomatitis outbreak


vesicular-stomatitis-august-27Nearly 400 horses have been affected by vesicular stomatitis since the outbreak in Texas and Colorado began in May.

The latest update from the Animal and Plant Health Inspection Service (APHIS), a division of the US Department of Agriculture, reveals that 38 new premises have tested positive for the disease across the two states in the last week.

The outbreak of the disease, which has symptoms similar to those of foot and mouth disease, has been affecting mainly horses. Testing has shown that the virus is the New Jersey serotype.

APHIS, in its August 27 update, provided a breakdown of latest properties confirmed with the disease. It said 35 new equine premises and one new property with both cattle and horses had been confirmed in Colorado, and one new equine property and one new cattle property had been confirmed in Texas.

It provided the following breakdown by county”


  • Bastrop County, Texas – 1 horse and 1 cow on 2 premises


  • Adams County, Colorado – 1 horse on 1 premises
  • Boulder County, Colorado – 7 horses on 6 premises
  • Broomfield County, Colorado – 1 horse on 1 premises
  • Jefferson County, Colorado– 5 horses on 3 premises
  • Larimer County, Colorado -19 horses and 3 cattle on 18 premises
  • Weld County, Colorado – 13 horses on 7 premises

To date, a total of 279 positive premises have been identified – 222 in Colorado and 57 in Texas.

There  have been eight counties affected in Colorado (Adams, Boulder, Broomfield, Douglas, El Paso,  Jefferson, Larimer, and Weld Counties) and 11 counties affected in Texas (Bastrop, Falls,  Guadalupe, Hidalgo, Jim Wells, Kinney, Nueces, San Patricio, Travis, Val Verde, and Williamson Counties).

Of the 279 total positive premises, 269 have been equine premises, 8 have been cattle premises, and 2 have had both cattle and horses positive.

Positive premises are eligible for quarantine release 21 days after lesions have healed in all affected animals.

To date, 15 premises in Texas have been released from quarantine (1 in Kinney County, 2 in Nueces County, 2 in San Patricio County, 2 in Hidalgo County, 1 in Jim Wells County, 1 in Val Verde County, 1 in Guadalupe County, and 5 in Travis County) and 17 in Colorado (6 in Boulder County, 10 in Weld County, and 1 in Adams County).

There are an additional 30 premises in Texas and 59 premises in Colorado on 21-day countdown to quarantine release.

To date, a total of 392 horses and 15 cattle have been infected since the outbreak started.


Vesicular stomatitis can cause blisters and sores in the mouth and on the tongue, muzzle, teats or hooves of horses, cattle, swine, sheep, goats, llamas and a number of other animals.

Lesions usually heal in two or three weeks.

Because of the contagious nature of the disease, animal health officials urge livestock owners and caretakers to report these symptoms to their veterinarian immediately.

Most animals recover well with supportive care by a veterinarian, but some lesions can be painful.

It is thought that insects are an important vector in the transmission of the disease.



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