The World Health Organization expressed alarm Thursday at the growing spread of H5N1 avian flu to new species, including humans, who are facing an “extraordinarily high” mortality rate.
“It remains, I think, a huge concern,” Jeremy Farrar, chief scientist at the U.N. health agency, told reporters in Geneva.
The current avian flu outbreak began in 2020 and has led to the deaths of tens of millions of poultry, with wild birds and terrestrial and marine mammals also infected.
Cows and goats joined the list last month – a surprising development for experts because they are not considered susceptible to this type of flu.
The A (H5N1) strain has become “a global zoonotic animal pandemic,” Farrar said.
“The big concern, of course, is that by infecting ducks and chickens and then increasingly mammals, this virus is now evolving and developing the ability to infect humans and then, critically, the ability to go from human to human.”
So far, there is no evidence that the influenza A(H5N1) virus spreads between humans.
But in the hundreds of cases where humans have been infected through contact with animals, “the mortality rate is extraordinarily high,” Farrar said.
From 2003 to April 1 this year, the WHO said it recorded 463 deaths from 889 human cases in 23 countries, bringing the case fatality rate to 52 percent.
Worryingly, US authorities said earlier this month that a person in Texas was recovering from bird flu after exposure to dairy cattle.
It was only the second human case to test positive for bird flu in the country, and it came after the virus sickened flocks apparently exposed to wild birds in Texas, Kansas and other States.
This also appears to be the first human infection with the A(H5N1) influenza virus strain through contact with an infected mammal, the WHO said.
When “you get into the mammalian population, you get closer to humans,” Farrar said, warning that “this virus is just looking for new, novel hosts.”
“It’s a real concern.”
Farrar called for increased surveillance, insisting that it was “very important to understand how many human infections are occurring… because that’s where the adaptation (of the virus) will happen.”
“It’s a tragic thing to say, but if I get infected with H5N1 and die, that’s the end of it. If I’m walking around the community and transmit the virus to someone else, then you start the cycle.”
He said efforts were underway to develop vaccines and treatments for H5N1, and stressed the need to ensure regional and national health authorities around the world have the capacity to diagnose the virus.
This was done so that “if H5N1 jumped to humans, with human-to-human transmission,” the world would “be able to respond immediately,” Farrar said, calling for equitable access to vaccines, treatments and diagnostics.
© Agence France-Presse
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