(Washington) A first death linked to avian flu has been recorded in the United States, Louisiana health authorities announced Monday, specifying that the deceased was an elderly patient who suffered from other pathologies.
This patient, aged over 65, was the first serious human case detected in the United States. He had been contaminated by the H5N1 virus through farmyard and wild birds.
Suffering from a respiratory ailment, he was in “critical condition”, health authorities reported in December, when his hospitalization was publicized.
The investigation “did not identify additional cases of H5N1 or evidence of person-to-person transmission.” This patient remains the only human case of H5N1 in Louisiana,” the local health department said on its website.
This is why he considers that the risk presented by avian flu for the general public remains “low”. As for “people who work with birds, poultry or cows, or who are exposed to these animals as part of their leisure activities”, the risk is “higher”.
For several months, the United States has been facing an epizootic – the equivalent of an epidemic in animals – of avian flu.
The virus circulates in poultry farms and in cattle herds and 66 cases of avian flu in humans have been detected since the start of 2024, the vast majority being benign and linked to known contacts with infected animals.
Although no cases of spread between humans have been observed, the level of circulation of the virus worries experts.
“I’m not worried about the average person, but about people who are in contact with animals that we know can be infected,” says Jennifer Nuzzo, professor of epidemiology at Brown University. And continued: “It’s a nasty virus that no one would like to catch. »
Exposure
“Although tragic, a death from the H5N1 virus in the United States is not unexpected,” the American Centers for Disease Prevention and Control (CDC) also recalled about the death reported in Louisiana.
“Outside the United States, more than 950 cases of H5N1 avian influenza have been reported to the World Health Organization, and about half of them resulted in death,” they report in a press release.
These cases were recorded between 2003 and the end of 2024 in 24 countries, including a large number in China and Vietnam, specifies a WHO document.
“The vast majority of cases of contamination and death are linked to known exposure” to a sick animal, notes M.me Nuzzo.
As things stand, this epidemic surveillance specialist is especially concerned that more people working on farms or in contact with wild animals “will fall ill and die”.
Furthermore, she emphasizes, if the Louisiana patient presented other pathologies, the case of a Canadian teenager hospitalized in 2024 for avian flu shows that younger and healthier people can also be seriously affected.
Avian influenza A (H5N1) first appeared in 1996, but since 2020 the number of outbreaks in birds has exploded and an increasing number of mammal species have been affected.
Risk of mutation
Experts fear that this strong circulation of the virus will facilitate a mutation allowing it to be transmitted from one human to another. Some also fear that it will mix with seasonal flu and thus become more transmissible.
Genetic sequencing of the virus found in the Louisiana patient showed that it was different from the version detected in several herds of dairy cows and on poultry farms.
And a small part of the virus showed genetic modifications suggesting that it may have mutated inside the body to adapt to human respiratory tract. However, this mutation is not the only one necessary to make a virus more contagious or transmissible between humans, reassure researchers interviewed by AFP.
As the inauguration of Donald Trump approaches, who has expressed his wish to eliminate an agency responsible for preparing for epidemic risks, the situation worries health stakeholders.
The outgoing administration is also not exempt from criticism, with experts deeming its response insufficient and warning of shortcomings in terms of contamination monitoring.
“We could do so much more,” says Jennifer Nuzzo, who calls in particular for strengthening prevention measures for agricultural workers, including through vaccination.
