South Dakota animal health officials have tightened rules on livestock coming into the state from Texas because of a confirmed case of a pesky, although not fatal, animal disease in that state.

A case of vesicular stomatitis, a disease that afflicts cloven-hoofed livestock and wildlife, was recently confirmed in a horse in Starr County, Texas.

All livestock entering South Dakota from Texas must be accompanied by a health certificate stating that the animals have not been exposed to the disease and have not come from areas quarantined for the disease. The restrictions went into effect Monday.

Normally, the health certificate must be obtained and signed 30 days prior to shipment, but now, for animals coming from Texas, the certificate must be obtained 72 hours prior to shipment, according to Dr. Dustin Oedekoven, acting South Dakota state veterinarian.

Oedekoven, who heads the South Dakota Animal Industry Board, announced the new requirements Monday.

He urged horse owners to consider changing their schedules if they had planned to travel to an area affected by the disease.

Currently, no other state other than Texas has confirmed the disease, although it is known to spread rapidly, Oedekoven said. Wyoming had several cases in 2006.

Vesicular stomatitis is a sporadic, re-emerging disease characterized by blister-like lesions on the tongue, lips and soft skin areas of hooved animals, including the udder.

VS has an incubation period of two to eight days. Infected animals develop blisters that swell and burst, leaving painful sores.

The disease is fairly mild, Oedekoven said.

"The reason it is of concern is it is so similar to foot-and-mouth disease," he said in a phone interview Monday. "We don't take it lightly."

The disease can be contracted by all cloven-hoofed animals, including cattle, horses, pigs, sheep and deer.

If the disease is found in South Dakota, the state will quarantine animals as well as farms and ranches, Oedekoven said.

Vesicular stomatitis can pose problems if found here, he said, because other states and nations can take actions similar to South Dakota's, tightening requirements to ship animals.

"It can get costly, especially for horse owners, because they're moving animals back and forth frequently," Oedekoven said.

Transmission of VS is not fully understood; however, it is known that the disease may be spread from animal to animal or by biting insects, Oedekoven said.

Infected animals also can spread the virus when their saliva or fluid from ruptured blisters contaminates feed, water or hay shared with herds.

VS infections usually run their course in two to three weeks, at which time animals begin healing, Oedekoven said.

VS is not a disease of humans, although there have been occasional reports of mild flu-like symptoms in individuals working closely with affected animals.