The Worst-Case Scenario

A top American animal health official warned Tuesday that the risks of a foot-and-mouth outbreak in the United States were great, as the Agriculture Department asked several federal agencies to help prepare for one.

That came amid a growing push to treat the foot-and-mouth threat as a matter of national security, reports CBS News Correspondent Sharyl Attkisson. Many believe the risk that foot-and-mouth will show up here grows, not lessens, with each passing day.

The director of the Agriculture Department's Plum Island laboratory, off Long Island, N.Y. — the only U.S. lab that studies and tests for foot-and-mouth disease — said Tuesday that the chances of an outbreak somewhere in the country are "quite great," given the amount people travel between the U.S. and Britain.

"It's only through the diligence of the people at the various ports of entry that we've been able to keep it out. I'll have to add also luck," said David Huxsoll.

"You've got to respond quickly, you've got to control the outbreak, prevent its spread and you need to move fast," said Dr. William Hueston, a veterinary professor at the Virginia-Maryland Regional College of Veterinary Medicine.

"We've always got to plan as if the disease is going to start tomorrow," he said.

To prevent the disease from coming here, USDA has banned imports of livestock and raw meat from the European Union, and stepped up checks at airports.

Agriculture Department officials, who would lead any response to a foot-and-mouth outbreak, say they're prepared for all scenarios, even the worst-case.

"We have adequate resources" to keep the disease out of the United States, "but we are going to continue to look at the systems that are in place," USDA spokesman Kevin Herglotz said.

Herglotz said there is "no greater risk today" of foot-and-mouth infecting U.S. livestock "than there was two weeks ago or a month ago."

The USDA Tuesday asked several departments and agencies — including Defense, Customs, CIA, Interior and the Federal Emergency Management Agency — to identify the resources that would be available to combat an outbreak.

It would have required 50,000 people, including military personnel, to contain the disease.

"In the worst-case scenario, all the agencies saw that it was overwhelming. I don't think this was a surprise," Herglotz said.

The multi-agency team will try to figure out if bio-terrorists could intentionally bring the virus to America, how quickly livestock could be quarantined and who would oversee and pay for the mass destruction of carcasses.

Foot-and-mouth disease is harmless to humans but has devastated livestock in Britain because herds are destroyed to prevent its spread. It is common throughout most of the world, including South America, but has not been found in the United States since 1929.

There is a vaccine, but the U.S. doesn't have nearly enough for widespread use, and it could also prove economically damaging.

"If you vaccinate then you actually introduce the virus into the herd, which is not a good thing," said Alisa Harrison, of the National Cattleman's Beef Association. "And second of all, it does impact your ability to export to other countries."

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