Bird flu is spreading “effectively” in rodents amid growing fears it could lead to a new pandemic, scientists have warned.
Experts described the discovery as “extremely disturbing”, saying it shows the pathogen is one step away from circulating among humans.
This is the first known study to clearly establish that individual mammals can not only contract the disease, but also spread it.
However, the death of infected mammals such as minks, foxes, raccoons and bears has shown that this is possible.
H5N1, the strain of avian influenza that caused the current global outbreak and is considered the largest ever, does not spread easily from person to person.
Some experts fear that virus mutations that facilitate transmission from mammals to mammals could make a difference.
There have been fewer than 900 reported human cases worldwide of the H5N1 virus, which kills nearly 50% of the people it infects.
The virus is usually contracted through close contact with an infected bird, either dead or alive.
The new study, which has not yet been peer-reviewed, has found that H5N1 can “cause a deadly disease in many mammalian species.”
Canadian researchers, including some public health agencies, have infected ferrets with one of four strains of the H5N1 virus.
Rodents were chosen for the study because they have a respiratory structure similar to humans, which gives experts an idea of how the virus interacts with humans.
They found that “direct contact” with one strain of the H5N1 virus isolated from an infected bird was “fatal”. This raises the possibility that the strain may have evolved “certain adaptations that provide a higher degree of replication, pathogenicity, and transmissibility.”
And they warned that if such a strain reaches humans, the consequences could be dire.
“Because there is little to no immunity to H5 in the population, if an H5N1 isolate capable of some sustained transmission makes the jump to humans, it would likely represent a devastating infection for the population,” they wrote.
John Fulton, a pharmaceutical industry consultant and founder of BioNiagara, said H5N1 is a threat “100 times worse than Covid.”
“This discovery is very alarming and governments should take immediate action to find and mobilize all high-potential manufacturing capacities for the production of vaccines and drugs for the prevention and treatment of H5N1 avian influenza,” he added.
And vaccine makers GSK, Moderna and CSL Seqirus have begun developing new human doses that target the rapidly spreading strain of the virus.
Others, such as Sanofi, have generic H5N1 vaccines available that can be adapted to the currently circulating strain.
As with other forms of the flu, people can become infected if they get the virus in their eyes, nose, or mouth, or if they breathe it in.
But in the case of bird flu, this usually happens in people who spend a lot of time with infected creatures.
In early 2023, a series of human cases of avian influenza were reported.
Earlier this year, a Cambodian man and his daughter were diagnosed with the H5N1 virus.
Their cases have raised international concern, with many experts fearing the infection is evidence that the virus has mutated to better infect people.
Further testing revealed that the Cambodian family did not have the H5N1 strain that is rapidly spreading among the world’s wild birds, but instead had a known variant circulating locally in the Prey Veng area where they lived.
Since the onset of the ongoing outbreak in October 2021, only one case of H5N1 has been reported in Briton.
Source: Daily Mail