"MINNEAPOLIS — The detection of a highly pathogenic strain of bird flu at a Tennessee chicken farm has poultry farmers stepping up security in an attempt to prevent an outbreak like the one in 2015 that required the destruction of millions of chickens and turkeys in the Midwest. The appearance of milder forms of bird flu at a Wisconsin turkey farm and another Tennessee chicken farm has heightened concern.

Here are some things to know about the state of avian influenza in the U.S. and worldwide, and how the poultry industry has tried to prepare for a recurrence:

The U.S. Department of Agriculture announced Sunday that a highly pathogenic form of bird flu was confirmed Saturday in a flock of 73,500 breeding broiler chickens in Lincoln County, Tennessee, after hundreds of birds began dying. It was identified as an H7N9 virus of North American wild bird origin. The USDA stressed that it was not the same H7N9 virus of Chinese lineage that has sickened poultry and people in Asia, nor is it related to the virus that caused the 2015 U.S. outbreak.

Officials quickly moved to kill the entire flock to prevent the virus from spreading. The affected farm supplies Tyson Foods Inc."

Steve Karnowski reports for the Associated Press March 9, 2017. [2]