(CNN) -- A poultry facility in southwest Missouri was quarantined after the discovery of a suspected case of bird flu, officials said.
"As a precaution, the poultry facility has been quarantined following preliminary results obtained during routine testing," the Missouri Department of Agriculture said in a news release.
Additional tests will authenticate the viral disease at the Polk County facility, the state said Wednesday, adding that it is extremely rare for humans to be affected by this type of bird flu.
Cargill Corp. will euthanize up to 15,000 younger birds exposed to older turkeys that tested positive for bird flu antibodies, said Mike Martin, director of communications for the company.
Martin said Thursday the older birds are being harvested at another Missouri location. Their meat poses no health risk, he said.
Flocks within six miles of the facility are being tested. Test results may be back as early as Friday, Cargill said.
"At the time the tests were conducted, the birds had no symptoms of the avian influenza. However, the antibodies mean at some time, the animal immune systems responded to the avian influenza," Martin said. "The flu could have been present in the water, ground, air or transmitted by other migrating birds."
Cargill owns the birds but uses the farm under a contract, he said.
"This flu is not transferable to humans," Martin said. "The real concern is for animals and the flu not being spread to other animal herds."
The U.S Agriculture Department is monitoring the situation.