For the first time, bird flu has killed a human patient in the United States. Beyond this dramatic news, several experts have believed for months that American health authorities are not taking sufficient measure of this public health threat.
"We haven't really made any effort to limit" the outbreak of bird flu in American cattle farms, Dutch virologist Marion Koopmans told AFP.
At the cost of a new pandemic, five years after the appearance of Covid? "It could start like that," warns Ms Koopmans, while stressing that the general public should not panic in the current state of affairs.
For now, the outbreak of bird flu is limited to animals. The sixty or so human cases recorded in the United States, including the one who died in recent days, were caused by direct exposure to an animal and the World Health Organization (WHO) specifies that no transmission between humans has been recorded.
But recent developments in the H5N1 virus that causes the disease are worrying researchers. Identified in 1996, it has long threatened only birds, millions of which have died since the start of the current epidemic in 2020.
This is no longer the case. The virus is now circulating in mammals, including, since March 2024, cattle farms in the United States.
Certainly, the patient who died in the United States, a relatively old man who had been hospitalized since December, had not been in contact with cattle but with birds. The fact remains that the virus's ability to mutate to reach mammals appears potentially dangerous, with the possibility of contamination from one human to another one day in sight.
– Opaque communication –
According to a study released Monday - but which has not been published by a scientific journal and independently reviewed - mutations of the virus in cattle are indeed likely to promote infection in humans.
For one of its authors, Tom Peacock, a virologist at Imperial College London, "the biggest mistake the United States made was its slow and weak response to the epidemic in cattle."
The reason bird flu is affecting cattle farms in the country appears to be a combination of this weak initial response, poor biosecurity and "the intensification of American dairy farming, which involves much more animal movement than in the European system," he told AFP.
Many experts also criticize the United States for not carrying out sufficient health surveillance of livestock farms and for communicating opaquely about the current epidemic.
"There's tons of data that the current administration has not made public," virologist Rick Bright, who has held senior positions in U.S. health authorities, told the Washington Post on Monday.
The expert is calling for allowing the deployment of H5N1 vaccines, currently stockpiled in the millions in the United States, to farm workers and other at-risk populations.
The calls for action are all the more urgent as President Joe Biden's administration is on its way out before Donald Trump takes office, who is scheduled to return to the White House on January 20.
But Mr. Trump chose Robert F. Kennedy Jr. as his health secretary, who holds both anti-vaccine positions and supports the consumption of raw milk, which is known to be easily contaminated with the bird flu virus.
The current government appears to have been more proactive recently, releasing more than $300 million last week to support surveillance and research into the bird flu outbreak.
And some experts refuse to cast stones at him: the United States "conducts significant surveillance," WHO spokeswoman Margaret Harris told AFP. "That's why we're hearing about it."
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