Posted: Friday, January 18, 2013 10:26 AM
State officials are awaiting test results before confirming what may be the first case of bovine tuberculosis in Washington since 1988.
In the meantime, they are assuming a meat sample from a Moses Lake, Wash., dairy is positive for TB, said Hector Castro, spokesman for the Washington State Department of Agriculture,
"It's 98 percent probable, but there is a culture that's being grown as a confirming test," Castro said, noting the test will take several weeks.
The state is not identifying the 1,500-cow dairy, as the investigation is ongoing. Investigators will test the rest of the herd at the dairy next week.
The cow had been sent to a Cowlitz County slaughter facility on Jan. 8, but the meat was held after a USDA Food Safety and Inspection Service inspector identified a suspicious lesion and submitted samples for testing.
The state has issued an order to stop the movement of cows on the dairy. As part of the order, any milk from the dairy will go straight to pasteurization, which kills the TB bacteria. Castro said the dairy primarily produces milk destined for pasteurization anyway.
The dairy purchased the cow about a year ago from a smaller dairy in Snohomish County, Wash.
At the time the cow was part of the Snohomish County dairy's herd, that business was dealing with milk processed for pasteurization. Since then, it sold its herd and purchased a smaller herd to focus on the raw milk market.
"This particular cow was not part of the current herd," Castro said. "Nevertheless, we are working with them to make sure the cows they are using for milk production are being tested for TB."
The Snohomish County dairy has been adhering to the annual requirement for TB testing, Castro said, but the state is being as cautious as possible.
Both dairy owners are cooperating, he said. The Snohomish County dairy voluntarily embargoed its raw milk until testing is complete.
It's too early to know all the movements of the cow in question or impacts to cows it may have come into contact with, Castro said, but the lesion found on the cow at the slaughterhouse was in early stages of developing.
"We may be fortunate here," Castro said. "If (it) had been sick even longer, then there's all the greater opportunity (it) would have been in contact with a much larger number of cattle."
Jack Field, executive vice president of the Washington State Cattlemen's Association, said that the state's ability to isolate the carcass in question indicates the system "clearly works."
The state will continue working with the Snohomish County dairy and schedule testing at the dairy in Moses Lake, Castro said.
"At the moment, we've taken the measures we're confident can contain it, but it's going to take a few days before we're able to do much more tracing to determine the actual source," Castro said.
Bovine TB, which is caused by the M. bovis bacteria, can be transmitted from livestock to humans and other animals, according to the USDA. The disease has nearly been eliminated from the U.S. livestock population.