Herds quarantined in mad-cow probe

WASHINGTON — Herds of cows are under quarantine in three states, and agriculture officials still lack full accounting of meat that was recalled after discovery of mad-cow disease in the United States a month ago.

Cows with links to the Holstein diagnosed with the brain-wasting disease have been found in Washington, Oregon and Idaho. More than 600 animals have been destroyed in the course of the investigation.

The disease has not been detected from tests on roughly 150 of those animals.

"It's not unusual for an investigation of this type to have multiple states involved," said Agriculture Department spokeswoman Julie Quick.

Investigators continue to look for about 70 cows that could have come to the United States from the same Alberta, Canada, farm where the sick Holstein was born in 1997. Suspicion focuses on those animals because scientists believe feed containing protein from infected animals is the most likely source of transmission of the disease.

Investigators also cannot rule out transmission from mother to calf.

Mad-cow disease, or bovine spongiform encephalopathy, is a threat because humans can develop a similar brain-wasting illness, a variant of Creutzfeldt-Jakob disease, from eating contaminated beef products.

Agriculture officials have insisted that the U.S. beef supply is safe, but they nevertheless recommended a recall of more than 10,000 pounds of meat from the sick cow and other animals slaughtered with it on Dec. 9.

USDA officials said the parts most likely to carry infection — brain, spinal cord and lower intestine — were removed before the meat from the infected cow was cut and processed for human consumption.

Most of the meat went to suppliers and stores in Oregon and Washington, and small amounts reached California, Idaho, Montana and Nevada. In all, 570 meat distributors, stores and restaurants received the recalled beef, but USDA officials said Friday they did not know how many pounds of beef were returned.

Some probably was consumed in the 14 days between the animal's slaughter and the mad-cow diagnosis, they said.

While consumer confidence in U.S.-grown beef has not declined noticeably, foreign markets remain closed to American beef amid a debate about the extent of restriction necessary to protect countries from potentially tainted meat.