Cases of vesicular stomatitis (VS) continue to be detected in Texas, New Mexico and Colorado, but the disease appears to be occurring at lower levels than in previous years’ outbreaks. As of July 24, nine premises in Texas and 11 in New Mexico are under quarantine, due to VS infection. In Colorado, 10 horses and three head of cattle are quarantined on premises in four counties. The viral infection, thought to be spread by sand flies or black flies, can cause horses, cattle and other livestock to develop blister-like lesions that can take several weeks to heal.

“Nationally, we’re seeing fewer cases than in l997, when the disease was confirmed on 380 premises before the outbreak ended in late fall,” said Dr. Max Coats, deputy director for Animal Health Programs for the Texas Animal Health Commission (TAHC), the state’s livestock and poultry health regulatory agency. “I don’t recall Texas ever having this many confirmed cases – a total of 11 so far -- or seeing them as far east as Starr County. Usually, Texas’ lone case or two is detected in far west Texas.”

“Even though the case numbers have remained fairly low, some states receiving livestock have imposed movement restrictions or testing requirements, as a precaution against potential disease spread,” said Dr. Coats. “Therefore, we urge livestock owners to check with the state veterinarian’s office in the state of destination prior to travel, to ensure all requirements are met. States with movement restrictions include Kentucky, Tennessee and New Jersey, which depend on their healthy horse industry.”

The country’s first confirmed case of VS this year was detected in horses on a premise Reeves County, Texas, in mid-May. The TAHC quarantine was released July 10, after a regulatory veterinarian inspected the livestock on the site several times and found the animals to be fully healed. Likewise, a quarantine in Val Verde County was released July 16, leaving nine premises in five Texas counties under VS quarantine. The quarantined premises include five sites in Starr County, two of which include infected cattle. Horses comprise the remainder of the Texas cases, located on one premise each in Dimmit, Uvalde, Kerr and Yoakum Counties. Maps can be reviewed at: http://www.tahc.state.tx.us.

Colorado currently has confirmed cases of VS in 10 horses and three cattle. The infection has been detected in Douglas, Las Animas, Park, and Pueblo counties. Updates on the Colorado cases can be accessed on the internet at: http://www.ag.state.co.us

New Mexico has horses on 11 premises in four counties under quarantine. These include six small premises “clustered” in Eddy County, near Carlsbad. Three sites in Valencia County remain under movement restriction, as well as one each in San Miguel and Grant counties.

“Please report signs of illness in livestock that resemble vesicular stomatitis,” urged Dr. Coats. “These can include blisters or erosions in an animal’s mouth or on the muzzle, on the teats, or above the hooves. VS can affect horses and other equine animals, cattle, deer, goats, swine and a number of other animals. Tests will be run at no charge to the owner, so that we can ensure that we are, in fact, dealing with VS, and not the highly dangerous foot-and-mouth disease, which exhibits similar signs of disease in cloven-hooved animals.” Dr. Coats noted that horses and other equine animals are not susceptible to foot-and-mouth disease, but tests can rule out other causes of illness, such as poison, toxic plants or other diseases.

To report potential signs of VS, owners and practitioners should contact their state veterinarian’s office, so a disease investigation and appropriate testing can be conducted:

Texas Animal Health Commission -- 1-800-550-8242
New Mexico Livestock Board -- 1-505-841-6161
Colorado Department of Agriculture, State Veterinarian’s Office – 1-303-239-4161