"I've watched foot-and-mouth disease occur on four different continents in what is historically a very short period of time," said Peter Cowen, a professor of epidemiology at the University of North Carolina. "I think the chances are not so much if but a question of when."
Many top veterinarians and regulators believe import bans and inspections at ports and airports should be enough precaution to safeguard the U.S. meat industry.
But others question whether inspectors can scrutinize every container being unloaded at the ports and check every questionable suitcase.
"We hope people are honest and answer the questions honestly," said Breitmeyer, the state veterinarian. "When you've got five or six different international planes landing at once, it's hard to check every passenger."
If travelers, taboo meat or other material were to introduce the disease in California, the results would be disastrous, costing dairymen and cattle ranchers an estimated $13.5 billion.
California's cattle and dairy industries, unlike other regions, have herds that range from the hundreds to the thousands, and these animals are usually kept penned together, eating the same feed rather than grazing pastureland.
"I think over the last two to three weeks, it's become a much more important issue to me as I've come to realize the devastation it could be to me," said rancher John Lacey of Paso Robles, Calif.
Cattleman John Harris has cowboys patrolling the 100,000 cows and bulls at his feed lot every day to make sure they are able to get up and do not have suspicious blisters or other symptoms of sickness, such as slobbering or lameness. He estimates that if the disease were introduced by an animal at the feed lot, these workers would identify it in less than 24 hours.
But by the time it was spotted, experts say, it would almost certainly have spread to other areas.
The U.S. and its North American Free Trade Agreement partners, Mexico and Canada, simulated a foot-and-mouth outbreak in November at a swine works near a Texas cattle ranch to gauge response times.
In the simulation, a single truck of infected animals was able to travel from Mexico to Canada before the outbreak it caused was confirmed.
Time is the most critical factor in preventing the kind of devastation that is playing out in Britain. At least that's the lesson from the last foot-and-mouth disease outbreak in the States in 1929.
That outbreak, first diagnosed at a Montebello hog farm, started with waste from a vessel at the Port of Los Angeles. Because the pig owner was able to immediately spot the symptoms and a diagnosis was delivered in three days, the disease was contained to five farms and resulted in the destruction of only 3,548 animals.
It was a far cry from the outbreak just five years earlier, when pigs on the infected farm were sick for weeks and it was three months before a state of emergency was declared. The animal death toll in that outbreak reached 109,855, according to information from the California Department of Food and Agriculture.
"Obviously, quick detection of the disease is critical," said Steve Kay, editor and publisher of Cattle Buyers Weekly in Petaluma, Calif.
"But the bottom line is we have to keep it out of the animal population completely," Kay said. "The government needs to be checking travelers even more thoroughly. We need greater bio-security on the farms and more resources to prevent smuggling."
Times staff writer Emily Green contributed to this report.