According to AFP, experts are starting to sound the alarm that the virus that is fueling an unprecedented rise in avian influenza cases worldwide is changing faster than previously thought and when the world’s attention is drawn to it. And if it happens, it can attack again.
Consequently, there is an increasing demand for countries to take action and vaccinate their poultry.
Although experts stress that the risk to humans is low, they are concerned about increasing cases of bird flu in mammals.
In talks with AFP, experts revealed that the H5N1 avian influenza virus, which first appeared in 1996, had previously been limited to seasonal outbreaks.
However, a significant change occurred in mid-2021. According to Richard Webby, director of the World Health Organization’s Collaborating Center for the Study of Influenza in Animals, this change significantly increased the infectivity of the group of viruses.
The implications of this change raise significant concerns among experts.
Since then, outbreaks have continued throughout the year, spreading to new areas and causing mass deaths of wild birds and tens of millions of chickens.
Webby, a researcher at St. Jude Children’s Research Hospital in the US city of Memphis, told AFP it was “absolutely” the largest outbreak of avian influenza in the world.
He led the research, published this week in the journal Nature Communications, showing how the virus evolved rapidly as it spread from Europe to North America.
The study found that the spread of the virus increased, meaning it caused more dangerous diseases when it arrived in North America.
The researchers also infected ferrets with one of the new strains of bird flu.
Wiebe said an unexpectedly “large” amount of the virus was found in his brain, indicating he had developed a more serious disease than the previous strain.
Stressing that the risk in humans is still low, he said “this virus is not static, it is changing”.
“This raises the possibility that just by chance the virus could pick up genetic traits that allow it to outcompete the human virus,” he said.
In rare cases, humans sometimes contract the deadly virus, usually after coming into close contact with infected birds.
Fears and admonitions.
The virus has also been detected in an increasing number of mammals, which Webby described as a “really, really troubling sign.”
Chile said last week that nearly 9,000 sea lions, penguins, otters, porpoises and dolphins along its northern coast have died from bird flu since the start of the year.
Most mammals are thought to have contracted the virus by eating an infected bird.
But Webby said what “frightens us the most” are indications from a Spanish mink farm, or sea lions off South America, that the virus could be transmitted between mammals.
Ian Brown, head of virology at the UK’s Animal and Plant Health Agency, said there was still no clear evidence that the virus could easily persist in mammals.
Brown told AFP that while the virus is evolving to become “more effective and more efficient in birds,” it is “unadapted to humans.”
Avian viruses bind to different receptors on the host cell than human viruses, Webby said.
“Two or three minor changes in a single protein of the virus” would be needed to make it more adaptable to humans, he said.
“That’s what we’re really looking for.”
– Vaccination of Poultry –
One way to reduce the total number of bird flu cases, and therefore the risk to humans, would be for countries to vaccinate their poultry, Webby said.
A few countries, including China, Egypt and Vietnam, have already launched vaccination campaigns for poultry.
But many other countries are reluctant because of import restrictions in some areas, and there are fears that vaccinated birds that are still infected could slip through the net.
In April, the United States began testing several vaccine candidates for potential use on birds.
France recently said it hopes to start vaccinating poultry as early as autumn this year.
Britain’s chief veterinary officer, Christine Middlemiss, said vaccinating poultry was “not a silver bullet because the virus is constantly changing”.
But traditionally reluctant countries should consider vaccinating poultry more often, Middlemiss told AFP at an event at the British embassy in Paris last week.
World Organization for Animal Health director-general Monique Elliott said vaccinating poultry should be “on the table”.
After all, “everyone now knows that the pandemic is not just a fantasy — it could be a reality,” he added.