Risk of mad cow infection very low.

Byline: Tim Christie The Register-Guard

What's the risk of eating beef now that a dairy cow in Washington state has been found with mad cow disease?

Most medical and animal science experts, as well as government officials, say the risk is very low.

You have to eat beef that contains cow brains or spinal cord to get the disease, said Dr. Paul Cieslak, a state epidemiologist.

A 2001 study by the Harvard Center for Risk Analysis found that control measures already in place would ensure that few if any additional animals would get sick if the disease were introduced in the United States and that it would be "extremely unlikely" to become established here. The study was commissioned by the U.S. Department of Agriculture.

Mad cow disease is the common term for bovine spongiform encephalopathy, or BSE, a progressive neurological disease of cattle. Scientists believe British cattle developed the disease after they were fed rendered meat-and-bone meal from cows and sheep.

Mad cow is part of a family of brain disorders known as prion diseases, that include scrapie in sheep; chronic wasting disease in deer and elk; and new variant Creutzfeld-Jakob Disease, or vCJD, in humans.

Here are answers to other frequently asked questions about the phenomenon:

What do these diseases have in common?

They all involve protein molecules in the brain, known as prions. Scientists believe prions fold over into abnormal shapes, become infectious and poke holes in the brain.

How are prion diseases spread?

Scientists believe they spread through consumption of central nervous system tissue, such as brains and spinal cords.

Can humans get mad cow disease?

No, but they can develop the related disease, vCJD. Scientists believe people who have developed vCJD were infected by consuming cattle products contaminated with infectious prions. The incubation period for vCJD is about 13 years.

How common is vCJD?

As of Dec. 1, a total of 153 cases of vCJD have been reported worldwide since 1995: 143 from the United Kingdom; six from France, and one each from Canada, Ireland, Italy and the United States. (The U.S. case was reported in a patient who lived in the UK before moving to the United States.)

What is prognosis for someone with vCJD?

The disease is incurable and invariably fatal.

Are certain cuts safer than others?

BSE has never been found in muscle meats, so boneless cuts of beef are considered safe. Bone-in beef is slightly higher in risk.

What about ground beef?

Consumer groups say ground beef that's processed using mechanized equipment can contain central nervous system material. But Jim Males, head of the Animal Sciences Department at Oregon State University, said ground beef comes mostly from younger cattle and BSE has never been identified in cattle younger than 30 months old.

What about milk and dairy products?

BSE is not carried in milk or dairy products.

Does freezing or cooking beef eliminate risk?

It does not.

What steps have government regulators taken to protect the food supply?

In 1997, they banned U.S. ranchers from feeding ground-up meat and bone meal to their cows. That practice is believed responsible for the epidemic that hit the the United Kingdom in 1990s.

However, the government hasn't yet banned spinal columns and neck bones from the human food supply.

Sources: Centers for Disease Control and Prevention, U.S. Department of Agriculture, Food and Drug Administration, Oregon State University, Oregon Department of Human Services, Center for Science in the Public Interest