April 4, 2001 (Washington) -- The U.S. remains free of both "mad cow" disease and its dreaded human counterpart, but additional precautions are crucial, experts warned at a Senate hearing today.
Mad cow disease, known formally as bovine spongiform encephalopathy (BSE), is a fatal brain-wasting condition that was first diagnosed in British cattle in 1986. It's now been found in native cattle in Belgium, Denmark, France, Germany, Ireland, Italy, Liechtenstein, Luxembourg, the Netherlands, Portugal, Spain, and Switzerland.
The human version of mad cow disease is a variant of the fatal Creutzfeldt-Jakob disease (CJD). It's believed to be contracted by eating certain parts of infected cattle. Some 97 people in the U.K. have died from this version of CJD, along with a few more individuals in mainland Europe.
Millions and millions of European cows have been destroyed as the affected countries race to remove the risk of human infection.
Several senators expressed concern on behalf of Americans who may be afraid of European travel, given the long-simmering beef scare.
But Richard Johnson, MD, a special disease adviser to the National Institutes of Health, noted that the numbers of infected cattle have plummeted in the U.K. and that fewer than a handful of human cases have been reported in other European countries. As for the risk of traveling to Europe and eating European beef, he said, "The danger of driving to the airport is probably greater."
The U.S. risk for any kind of BSE spread -- cattle or human -- is "very low" but "not zero," said disease expert Will Hueston, associate dean of the Virginia-Maryland Regional College of Veterinary Medicine.
"Importation of affected animals and contaminated products of animal origin, such as meat and bone meal, represent the greatest risk for introduction of BSE to the U.S.," Hueston said.
Through restrictions going back to 1989, the U.S. has banned imports of cows and other cud-chewing animals from countries with the disease, as well as feed and other products derived from these animals. In 1997, the government banned the use of most cattle feed that contains animal protein. In Europe, BSE is believed to have spread through feed that contains tissue from infected cows. The U.S. government also is monitoring the nation's cattle herds, but examination of more than 12,000 suspect cows has thus far turned up no signs of the infection.