WASHINGTON — The Centers for Disease Control and Prevention (CDC) announced Wednesday that a Louisiana resident has contracted the nation’s first severe case of highly pathogenic avian influenza (H5N1), also known as bird flu. The unidentified individual is believed to have been infected through contact with sick or dead birds on their property, which were not part of a commercial poultry flock. Federal public health officials declined to release further details, citing patient confidentiality.
Previously, most U.S. cases of H5N1 resulted in mild illness, such as conjunctivitis and mild respiratory symptoms, with full recovery. However, Demetre Daskalakis, director of the CDC’s National Center for Immunization and Respiratory Diseases, noted that over two decades of global experience shows H5N1 infection can cause severe illness, even death, in up to 50% of cases in other countries. This severity underscores the importance of the coordinated U.S. federal response, known as the One Health response, to manage ongoing outbreaks in dairy cows and poultry and prevent further human transmission.
Despite this severe case, the CDC maintains that the threat to the general public remains low. The Louisiana Department of Health reported that the patient, who is over 65 and has underlying medical conditions, is hospitalized in critical condition with severe respiratory illness related to the H5N1 infection.
This year, the CDC has confirmed 61 human cases of H5N1 across nine states. However, the Louisiana case is the first to be classified as severe. The CDC declined to specify the patient’s symptoms or explain why this case differs from a Missouri resident hospitalized with bird flu, who was not categorized as having a severe case, citing patient privacy. The Missouri patient, hospitalized in August, had significant underlying medical conditions and experienced acute symptoms including chest pain, nausea, vomiting, diarrhea, and weakness.
The ongoing bird flu outbreak has affected wild birds and poultry flocks across the U.S. for years. However, the infection of dairy cattle began in March. The USDA reports that 865 dairy herds across 16 states have been affected, with 315 new cases in the past month, primarily in California. Nearly 124 million poultry have been affected in 49 states.
In response, the USDA expanded its nationwide milk testing strategy earlier this month to 13 states: California, Colorado, Indiana, Maryland, Michigan, Mississippi, Montana, New York, Ohio, Oregon, Pennsylvania, Vermont, and Washington. This program requires those responsible for dairy farms to provide unpasteurized milk samples for testing. California Governor Gavin Newsom declared a state of emergency to enhance preparedness and accelerate the response. The USDA also continues a voluntary bulk milk testing program for farms shipping cattle across state lines.