Mad Cow, Foot-And-Mouth Diseases Causing Confusion

Is there any connection between the outbreaks of mad cow disease and foot-and-mouth disease that have dominated international news lately?

No, the two diseases couldn't be more different, says Sam Winfree, an animal science professor at Tennessee Tech University.

"There's a lot of misinformation and misunderstanding about mad cow disease and foot-and-mouth," said Winfree, who teaches a course on animal diseases. "But these diseases, in many ways, are as different as two diseases can be."

The United States has not had a case of foot-and-mouth disease, a contagious virus, since 1929. Quarantine and slaughter, much like what is happening in Europe now, eliminated the virus from the country. The disease causes blistering of the mouths and feet, lameness, loss of appetite and wasting in many species of animals, but is not transmitted to humans.

"Foot-and-mouth disease is highly contagious; it can be carried by the wind, be walked into the country in the dirt on a person's shoes, or it can be carried by any warm blooded animal," said Winfree. "One rat carrying the disease that jumps off a ship from a foreign port can be the beginning of a big problem.

"If you've ever had chicken pox or a fever blister, you've had something similar to foot-and-mouth disease," said Winfree. "But the virus is not a threat to humans and does not survive outside a living animal."

On the other hand, Winfree says the cause of mad cow is unlike any other contagious disease -- it's not a bacteria or a virus. It is an infectious protein called prion with no nucleus, so to multiply it aligns with other proteins in body cells, is reproduced or copied, and eventually causes spongy deterioration of brain and stem tissues.

"Scientists have steamed it, cooked it, irradiated it and still haven't found a way to destroy this prion," said Winfree. "It seems it can survive forever in the ground."

Should we be worried about outbreaks of either disease?

"Economically, I'd be very concerned about foot-and mouth," said Winfree. "If we could control our borders, that would eliminate the concern. But as contagious as this virus is, it may prove to be difficult to prevent people, ships or airplanes from carrying the disease into the country."

Winfree said he's had two British students studying with him at Tennessee Tech for several years, and they've watched closely the economic devastation in Europe due to mad cow disease and now foot-and-mouth disease.

"We're not just talking about the economics of the agriculture community," he said. "Retail and tourism are all related economically to what happens."

Winfree says he's not particularly concerned about mad cow disease occurring in the United States because imports of foreign animals and animal products were stopped in the early 1990s, as was the practice of using feed made of animal by-products. Fortunately, mad cow disease has never been observed in cattle in the United States.

His best advice is to listen carefully to what is being said about each disease and don't let misunderstanding, fear or misconceptions cause undue worry. Recognize that these two problems are unrelated and quite different from each other.

"People tend to screen what they hear based on their fears," said Winfree. "Education is the best way to combat the confusion."

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