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.

The Louisiana Department of Health announced Jan. 6 that a patient hospitalized last month for H5N1 bird flu has died, becoming the first U.S. death from the virus. The agency said the individual contracted the virus after exposure to a combination of a backyard flock and wild birds.