As the "mad cow" crisis plays on in Europe, American consumers and beef producers are asking if this same nightmare could occur here in the United States.

The experts won’t mark bovine spongiform encephalopathy (BSE) off as a potential disease threat - scientifically, there are too many unanswered questions about its origin, cause, and transmission -  but they are saying that the chances are very low that BSE could appear in U.S. cattle.

The National Cattlemen’s Beef Association (NCBA) reports that a recent scientific report, conducted by the U.S.-based Council for Agricultural Science and Technology (CAST), found a very low risk for U.S. occurrence of BSE.

The cooperation cited in the CAST report, both within the industry and between the industry and the government, is a hallmark of the U.S. BSE program and a major reason for our success in preventing this disease, says NCBA CEO Charles Schroeder.

The U.S. Department of Agriculture’s policy regarding BSE is one of proactiveness and prevention. BSE measures taken by USDA’s Animal Plant Health Inspection Service (APHIS) include surveillance, prevention, education, and response.

To-date, no cases of BSE have been confirmed in the U.S., despite 10 years of active surveillance, reports USDA-APHIS. The surveillance program involves several government agencies and more than 250 federal and state regulatory veterinarians who have been trained to diagnose foreign animal diseases, including BSE. Additionally, BSE is a notifiable disease, by law, which makes it reportable by accredited veterinarians.

Even before the surveillance program was instituted in 1990, U.S. government response to the BSE issue was decisive and aggressive, reports NCBA. In July 1989, with U.S. cattle industry support, USDA-APHIS instituted a ban prohibiting importation of live ruminant animals from countries with confirmed cases of BSE. This was followed in November 1989 by an additional ban on at-risk ruminant products from those countries.

"An example of swift response and cooperation was the U.S. industry’s reaction to information that feed, which included meat and bone meal, might have caused the spread of BSE in England," says Schroeder.

In addition, Schroeder said NCBA also urged the Food and Drug Administration’s (FDA) Center for Veterinary Medicine to review the science and develop regulations regarding use of meat and bone meal in feeds for ruminants.

While the European Union is only now beginning to impose wide-scale bans on use of animal-derived protein supplements in cattle feed, the U.S. took that step more than three years ago, Schroeder says.

In June of 1997, the FDA issued a regulation banning the use of at-risk mammalian protein in animal feed. Limited exceptions include blood, milk, or gelatin products, and equine and porcine protein (including meat and bone meal), which is derived from species not known to develop TSEs naturally.

In December of 1997, USDA-APHIS took a major step by banning imports of all live ruminants and at-risk ruminant products from all of Europe until risk factors associated with BSE were more fully examined. And, as of December 2000, USDA-APHIS prohibits all imports of rendered animal protein products from Europe, regardless of species.

BSE, widely known as "mad cow disease," is a chronic, degenerative disease affecting the central nervous system of cattle. USDA-APHIS reports that, worldwide, there have been more than 178,000 cases since the disease was first diagnosed in 1986 in Great Britain. More than 95 percent of all BSE cases have occurred in the United Kingdom, with most in dairy cows between 3 and 6 years of age. Brain tissue of suspect animals is examined for infection; researchers are working on tests that can identify infected live animals.

Scientists are unsure how BSE originated; however, USDA-APHIS reports that data suggest the disease is a common-source epidemic involving animal feed containing contaminated meat and bone meal as a protein source. The disease unknowingly spread in the United Kingdom in the 1980s before control measures could be put into place.

Time Line

• 1989 — The importation of ruminants is banned from countries with confirmed cases of BSE. Also restricted is the importation of at-risk ruminant products from these countries.

• 1990 — Active surveillance for BSE begins in the U.S; USDA-APHIS develops a response plan in the event a case of BSE is detected in the U.S.

• 1991 — USDA-APHIS restricts the importation of ruminant meat and edible products and bans at-risk by-products of ruminant origin from countries known to have BSE.

• 1993 — USDA-APHIS expands BSE surveillance program to include examination of brain tissue from "downer" cows.

• 1994 — USDA-APHIS implements immunohistochemistry testing method for BSE.

• 1996 — A USDA-APHIS and Food Safety Inspection Service (FSIS) working group update the BSE response plan.

• 1997 — FDA bans the use of at-risk mammalian protein in animal feed, with limited exceptions. USDA-APHIS prohibits the importation of live ruminants and at-risk ruminant products from all of Europe.

• 2000 — USDA-APHIS prohibits all imports of rendered animal protein products from Europe, regardless of species.