‘This must be treated with the utmost concern’ warn scientists as bird flu mutates to infect people
A strain of bird flu has evolved to better infect human cells in a worrying sign.
The scientists on the ground who made the discovery said the discovery “must be treated with the utmost concern”.
The bird flu strain known as H5N1 claimed the life of a schoolgirl in Cambodia last week.
The scientists said there were “some indications” that the virus had already “passed through” a human and picked up the new mutations before infecting the girl.
The 11-year-old girl, from Prey Veng province, became the first victim of H5N1 in 2023. Her father also tested positive for the virus but did not develop symptoms.
Dr Erik Karlsson, who led the team from Cambodia’s Pasteur Institute that decoded the genetic sequence of the girl child’s virus, warned that it differed from that taken from birds.
He told Sky News: “There are indications that this virus passed through a human.
“Each time these viruses enter a new host, they undergo certain changes that allow them to replicate a little better or potentially bind a little better to cells in our airways.”
However, he added that the virus had not yet fully adapted to humans, saying it was basically “still a bird virus”.
The strain in its current form is unlikely to cause a major outbreak. Large-scale transmission would require a mutation allowing it to bind to a receptor present on the cells of the nose.
Genetic testing revealed that the girl had caught the 2.3.2.1c strain of H5N1, which is endemic to wild birds and poultry in Cambodia.
This differs from type 2.3.4.4b which spread rapidly around the world and infected many birds and mammals, but Dr Karlsson said that was no reason to downplay the threat.
He added: “It was a zoonotic overflow [of a virus infecting a new species] and should be treated with the utmost concern.
Calling on the world to continue to monitor the virus, he said: “Something can happen here in Cambodia and something can happen on the other side of the world in South America, but we don’t really know what could cause the problem tomorrow.”
H5N1 has a human mortality rate of about 50 percent. There have only been around 870 cases among people worldwide.
The 2.3.4.4b strain has devastated the world’s bird population over the past year.
