The first U.S. bird flu death has been reported. Louisiana health officials announced the death Monday of a person who had been hospitalized with severe respiratory symptoms.

The U.S. reported its first human death from H5N1 bird flu, marking a significant milestone in the outbreak. The patient was over 65 with underlying health conditions and was hospitalized in Louisiana in December.

The patient, who was older than 65 and had underlying medical conditions, was hospitalized weeks ago in critical condition with severe respiratory illness.