State and federal authorities are investigating an outbreak of bird flu on a poultry farm in western Kentucky.
State Veterinarian Robert C. Stout said the strain discovered is "nonpathogenic or low-pathogenic" and poses a minimal risk to human health. Stout said it is not the "high pathogenic strain" associated with human and poultry deaths in other countries.
Stout quarantined the farm, which produces hatching eggs for Perdue Farms Inc. He said some 20,000 chickens have been euthanized.
"It does occur naturally in wild birds and it can spread to domestic birds, which is why we have the occurrence in Kentucky," said Cindy Ragin, a spokeswoman for the U.S. Department of Agriculture. "This is something that is not uncommon."
Stout declined to identify the farm, but he said it is near Brownsville in Edmondson County.
"The state and federal government and Perdue are acting aggressively to contain and eliminate the disease," Stout said. "There is no evidence that any infected poultry are in the human food supply as a result of this infection. We will do what is necessary to minimize the disruption to overseas trade."
Already, Stout said, Japan and Russia have banned imports of poultry from Kentucky.
The Kentucky Department of Agriculture is conducting surveillance on backyard flocks within a two-mile radius of the farm.
"The people of Kentucky and our trading partners should rest assured that we are doing everything possible to address the situation," Agriculture Commissioner Richie Farmer said.
Stout said a minimal drop in egg production at the farm was noticed in mid-March. Perdue's veterinary services laboratory took samples from chickens at the farm and found antibodies for avian influenza.
Testing by the National Veterinary Services Laboratory in Ames, Iowa, resulted in a presumptive positive finding for the H7 strain. Subsequent testing by NVSL and the Breathitt Veterinary Center in Hopkinsville confirmed the finding.
Stout said it was the first confirmed case of bird flu in Kentucky.
In 2007, two outbreaks occurred in turkey farms in Virginia and West Virginia. Some 25,000 turkeys had to be euthanized on each farm after the pathogenicity avian influenza was discovered.
Bird flu is a virus that affects domestic poultry and some wild birds. It is spread by direct contact with infected birds.