Three influenza A (H5N1/bird flu) virus particles (rod-shaped). Credit: CDC and NIAID

WASHINGTON - The first human death linked to bird flu has been reported in the United States, health authorities in Louisiana announced Monday, while noting the patient had underlying medical conditions.

The patient, aged over 65, had been hospitalized for a respiratory ailment, and was the first serious case of human infection of the H5N1 virus to be detected in the United States.

The announcement in mid-December of the patient being in "critical condition" sparked alarm that the United States could see an outbreak of a possible bird flu pandemic, with similar cases reported worldwide.

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"The patient contracted H5N1 after exposure to a combination of a non-commercial backyard flock and wild birds," the Louisiana Department of Health said in a statement.

Despite this death, the public health risk posed by bird flu remains "low," the statement said, adding that it had detected no human-to-human transmission.

"While the current public health risk for the general public remains low, people who work with birds, poultry or cows, or have recreational exposure to them, are at higher risk," it warned.

Genetic sequencing has shown that the H5N1 virus that infected the Louisiana patient was different from the version of the virus detected in many dairy herds and poultry farms around the country.

H5N1 was first detected in 1996, but since 2020, the number of outbreaks among bird flocks has exploded, while a growing number of mammal species have been affected.

Experts are concerned that a high circulation of the virus in mammals could lead to mutations that make it more easily spread among humans.

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