WASHINGTON -- A second US animal has tested positive for mad cow disease, Agriculture Department officials said last night. The sample, from a downer cow in Texas that died last November, was retested earlier this week at the request of the USDA inspector general's office.
The animal had been deemed disease-free last fall, but when a sample was subjected to a more precise test, the result a ''weak positive," according to USDA Secretary Mike Johanns. He said that because of the differing results from the two tests, the sample would be sent next week to the world's top mad cow lab in Weybridge, England, for a final set of testing.
Johanns said repeatedly last night that the new result did not mean that people face any greater health risk from eating beef because meat from the animal did not enter the human food chain, or the beef feed chain. He also said the result should not have an impact on long and difficult negotiations under way to resume the exporting US beef to Japan and Korea, or the re-opening of the Canadian border to live cattle.
But if the positive finding is confirmed in England, the international reaction against US beef that occurred when a Washington state dairy cow tested positive in December 2003 could be repeated.
While the first US mad cow case involved an animal born and raised largely in Canada and then shipped to Washington state, USDA chief veterinarian John Clifford said last night that the agency had ''no information" that the possible second case was ''an imported animal."
He said the Texas animal was a beef cattle and was older but declined to give any more specifics. He did not indicate, for instance, whether the animal was born before or after the United States implemented a ban on feeding animal parts to cows in 1997. Mad cow infection is only known to spread through the consumption of beef parts that were fed to some cows in the 1990s, and the 1997 feed ban was designed to keep mad cow disease from spreading through the US herd.
The USDA has also been trying to lift a US ban on live Canadian cattle that was imposed after Canada's first BSE case in May 2003.
The border was scheduled to reopen in March, but a federal judge in Billings, Mont., ordered a temporary halt at the urging of beef ranchers and producers who argued the Canadian BSE-prevention system was inadequate.
An appeal on that decision is scheduled for next month, and a full trial it scheduled for late in July.