A Louisiana man has become the first person in the United States to die of avian influenza, state health officials reported Monday.
The patient, who was older than 65 and had underlying medical conditions, was hospitalized weeks ago in critical condition with severe respiratory illness related to the H5N1 bird flu virus. The patient, whom people familiar with the investigation have identified as a man, had been in contact with sick and dead birds in backyard flocks on his property, state health officials said in a statement.
The Louisiana patient’s death does not change the overall assessment by the Centers for Disease Control and Prevention of the immediate risk to the public’s health from H5N1 bird flu, which remains low. The CDC has expanded its recommendations for testing and treatment of bird flu during the past few months for anyone with high-risk exposure, primarily farm workers.
The Louisiana Department of Health did not provide details about when the patient died or what treatment he received.
State health officials said they have identified no additional H5N1 cases in residents, nor evidence of person-to-person transmission.
“The Department expresses its deepest condolences to the patient’s family and friends as they mourn the loss of their loved one. Due to patient confidentiality and respect for the family, this will be the final update about the patient,” the statement said.
Since April, at least 66 cases of bird flu have been reported in the United States, but almost all the patients had mild illnesses – pink eye or respiratory symptoms – and, until the recent death, all had recovered. Most of those who fell ill are dairy or poultry farm workers.
The virus that sickened the Louisiana patient is related to a version of bird flu recently found in wild birds and poultry in the United States and in people in British Columbia, Canada and Washington state, according to the CDC. It is different from the version of the virus associated with a widespread outbreak in dairy cows, some poultry outbreaks and a few other human cases in the United States.
A British Columbia teen was hospitalized in November in critical condition, unable to breathe on her own, with an infection caused by viruses from the same genotype that infected the Louisiana patient. The 13-year-old remains in the hospital but is no longer in the intensive care unit, according to David Goldfarb, one of the doctors caring for her at British Columbia Children’s Hospital in Vancouver.
CDC officials have said cases of severe H5N1 illness and deaths are not unexpected.
“CDC is saddened by Louisiana’s report that a person previously hospitalized with severe avian influenza A(H5N1) illness (“H5N1 bird flu”) has passed away,” the agency said in a statement. “While tragic, a death from H5N1 bird flu in the United States is not unexpected because of the known potential for infection with these viruses to cause severe illness and death,” the agency said. It noted the many cases of bird flu that have been reported globally, as well as the high mortality rate.
H5N1 emerged in 1997 and has spread widely around the world by migratory birds, resulting in infections in animals on every continent. Since H5N1 emerged, close to 1,000 people have been diagnosed with the viral ailment in 24 countries, with nearly half of those illnesses resulting in death, according to the World Health Organization.
In the ongoing U.S. outbreak, no person-to-person spread of bird flu has been detected. But testing showed that in the Louisiana patient and the Canadian teen, the virus possessed mutations that might allow it to more easily infect people.
Genetic analysis based on samples from the Louisiana patient showed signs that the virus could better attach to cells in humans’ upper airways, the CDC reported recently. Bird flu viruses normally attach to a cell receptor that is rare in human upper airways, which is one of the reasons H5N1 doesn’t easily infect people and does not spread person-to-person when it does, experts have said.
The CDC said the changes probably occurred while the virus multiplied in the gravely ill Louisiana patient. Genetic analysis of the virus in wild birds and poultry in Louisiana, including poultry on the patient’s property, and in other parts of the United States, did not detect similar viral changes.
Virus from poultry tested on the patient’s property did not have the changes found in the patient, “strongly suggesting that the changes emerged during infection as virus replicated in the patient,” the CDC said.
Such changes would be more concerning, experts said, if they were also found in animals or within a few days of the start of symptoms, because that would suggest the virus was already acquiring these mutations.
Canadian health officials have not determined how the British Columbia teen became infected.
(c) 2025, The Washington Post · Lena H. Sun