"We're trying to eliminate people from coming onto our farm that have been in a foreign country in the last 30 days," said Bob Nutter of Maple View Farm in Orange County.

To do that, the dairy farm, which receives a lot of visitors, has put up a sign that doesn't yet say "Keep out," but it does ask people to think about it.

"We put up a sign in our driveway that says if you've been in a foreign country in the past month, please refrain from coming in," Nutter said. "The only next step we could do here is keep anybody from coming to visit us."

Some hog farms in the state already are prohibiting people from entering their farms, he said.

"We haven't done that yet because the kids like to come and see the cows being milked," Nutter said.

Although foot-and-mouth disease hasn't been detected in the United States, "livestock producers in this country need to be cautious about visitors, particularly from Europe," said Karen McAdams, the livestock agent for Orange and Durham counties.

"It's a very contagious disease, much more so than other animal diseases," she said.

The virus mainly affects cattle, pigs, goats and sheep, and is spread by direct or indirect contact. Symptoms can show between 24 hours and 10 days after contact.

Foot-and-mouth disease doesn't cause illness among humans, but they can pass it to animals and there has been one recorded case - in 1966 in Britain - of a human developing the disease with mild symptoms.

Economic factors, rather than health and safety issues, explain the concern with foot-and-mouth disease.

Because a cure hasn't been developed, outbreaks could produce massive production losses, as witnessed by Great Britain.

According to a recent CNN study, the United Kingdom is losing an estimated $12 million per week in sales and has set up exclusion zones with a 10-mile boundary around all farms believed to be infected.

Already more than 180 cases of foot-and-mouth disease have been reported in the United Kingdom, and that number is expected to rise until the ailment is contained.

"If the disease were to reach here, everything in the animal industry would be completely shut down; it would be a major undertaking," said Charles Kirkland, director of field forces for the veterinary division of the N.C. Department of Agriculture and Consumer Services.

"I don't know how soon they can get it under control, I just hope they can keep it out of the United States," Nutter said. "It's a real possibility that it could get into North Carolina."

The possibility is so real that international flights arriving in Raleigh and Charlotte are greeting passengers with public announcements cautioning them not to be around animals for at least five days once they return, Kirkland said.

The precautions are "common-sense measures," he said.

"It's highly contagious and there are many ways of coming into the country, so we have to be very cautious," he said.

Contemplating the worst, Nutter said that if foot-and-mouth disease did reach his farm, "all livestock would be gone."