Bird flu, also known as avian influenza or H5N1, has infected more than 130 million birds over the past two years as it threatened commercial bird operations and recently led to the first human death in the United States.

Louisiana has reported the first U.S. fatality from avian influenza. Most of the country’s human cases have been mild

The first human bird flu death was reported out of Louisiana on Monday, Jan. 6. The same case was the first serious case of H5N1 in humans in the U.S.