Tennessee's state veterinarian says the the strain of bird flu discovered in March in Middle Tennessee has not spread to multiple poultry farms.

Dr. Charles Hatcher lifted the poultry health advisory and released the control zone surrounding that area Wednesday. He said extensive testing determined that the disease did not spread outside of the state' 10 kilometer control zone.

State officials discovered the first strain of the disease on March 4 in Lincoln County. They discovered a second infection at a farm about two miles away on March 14. Officials euthanized and buried both flocks. They also monitored birds at commercial and backyard farms within the control zone.

Workers at each infected farm are still cleaning and disinfecting those facilities.

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“We greatly appreciate the hard work of all involved in this response,” Commissioner of Agriculture Jai Templeton said. “From our staff and partners on the local, state and federal level to the flock owners and all connected to the poultry industry—this was truly a team effort. I certainly hope Tennessee never has to deal with this situation again, but should we face another challenge, I am confident that our state is prepared.”

Birds at a farm in Giles County also tested positive for a low pathogen version of the disease on March 8. The birds in that flock were euthanized and buried. The state veterinarian cleared a control zone there on March 30.

State agriculture officials say neither of these infections posed any risk to the food supply.