An avian flu strain that claimed the life of a schoolgirl in Cambodia has evolved to better infect human cells, which is a worrying sign.
On-site scientists who made the discovery said the finding “should be treated with great care.”
They added there were “some indications” that the virus had “passed through” a human before infecting the girl.
The 11-year-old girl from Prey Veng province became the first victim of H5N1 last week in 2023.
Her father has also tested positive for the virus, but has not developed any symptoms.
A worker catches chickens at a market in Phnom Penh on Feb. 24, 2023. The father of an 11-year-old Cambodian girl who died of bird flu earlier this week tested positive for the virus, health officials said
A young girl from Prey Veng in Cambodia (see map) died of H5N1 bird flu this year. She was infected with the virus in mid-February and is the first case in the country since 2014
Like all flu, the virus is primarily spread through airborne droplets that are inhaled or enter a person’s mouth, eyes, or nose
Dr. Erik Karlsson, an emerging disease expert who led the team at Cambodia’s Pasteur Institute that decoded the genetic sequence of the girl’s virus, warned that it differed from that of birds.
He told sky news: ‘There are some indications that this virus passed through a human being.
“Every time these viruses invade a new host, they go through certain changes that allow them to replicate a little better or possibly bind a little better to the cells in our airways.”
But he added that the virus had yet to fully adapt to humans, saying it was “still an avian virus.”
He said it was unlikely that the mutations had occurred in the girl, but that they probably existed in a “cloud” of viruses with random genetic changes in birds.
The H5N1 strain, which has a human fatality rate of about 50 percent, has caused record deaths among wild birds and domestic poultry over the past 18 months.
But Cambodia’s cases have raised concerns that the virus is adapting to infect humans.
The pathogen has already jumped from birds to mammals, raising fears that it is now a step close to spreading in humans — a hurdle that has so far prevented it from causing a pandemic.
Genetic testing for the virus was performed in just 24 hours, scientists said.
It revealed that the girl had caught the 220.127.116.11c strain of H5N1, which is endemic to wild birds and poultry in Cambodia.
This differs from the type 18.104.22.168b which has spread rapidly around the world and infected many birds and mammals, but Dr. Karlsson said this was no reason to downplay the threat.
He added: “This was zoonotic spillover (from a virus infecting a new species) and should be treated with great care.”
He called on the world to continue to monitor the virus, saying: “Something might happen here in Cambodia and something might happen on the other side of the world in South America, but we don’t really know what tomorrow will be.” can cause problem. .’
Health authorities in Cambodia say there is no evidence yet that the virus spreads between humans.
But Or Vandine, the country’s health secretary, added that the possibility cannot be ruled out on Monday. She said we should “wait” for the conclusions of experts investigating the cases.
The 11-year-old girl’s infection in Cambodia began six days before her death with fever, cough and sore throat.
Health experts work during disinfection in a village in Cambodia’s Prey Veng province where a father has been diagnosed with bird flu
Before the cases in Cambodia, only one case of H5N1 had been detected in humans this year. Cases in humans have been rare in recent years
New outbreak of human bird flu cases in Cambodia has sparked fears a new Covid-like pandemic is on the way
She was taken to a children’s hospital in Phnom Penh, the capital, about 100 km away.
Her father also tested positive for the virus — but had no symptoms — and has since tested negative.
It is possible that the 49-year-old from Prey Veng province also had to deal with infected birds.
His young daughter, who has not been given a name, is said to have fallen ill.
Bird flu outbreak: everything you need to know
What is it?
Bird flu is a contagious form of flu that spreads among birds.
In rare cases, it can be transmitted to humans through close contact with a dead or live infected bird.
This includes touching infected birds, their droppings or bedding. Humans can also get bird flu if they kill or prepare infected poultry to eat.
Wild birds are carriers, mainly through migration.
As they clump together to reproduce, the virus quickly spreads and is then carried to other parts of the world.
New species usually appear first in Asia, from where more than 60 species of shorebirds, waders and waterfowl migrate to Alaska to mingle with migratory birds from the US. Others go west and infect European species.
Which species is currently spreading?
So far, as of September 2021, the new virus has been detected in some 80 million birds and poultry worldwide – double the previous record set the year before.
Not only is the virus spreading rapidly, but it is also killing at an unprecedented level, leading some experts to say it is the deadliest strain yet.
Millions of chickens and turkeys in the UK have been culled or quarantined, affecting the availability of turkeys and free-range eggs.
Can it infect humans?
Yes, but only 860 human cases have been reported to the World Health Organization since 2003.
The risk to humans is estimated to be ‘low’.
But people are urged not to touch sick or dead birds because the virus is deadly, killing 56 percent of people it manages to infect.
She was Cambodia’s first human case since 2014.
None of the 29 others who were swabbed for the highly pathogenic virus were infected, the results showed.
Yesterday, the Centers for Disease Control and Prevention (CDC) said it was ramping up its pandemic preparedness in response to the threat.
The agency said it was in a “posture of preparedness” with several vaccine candidates and drugs in the works.
National testing capacity was also built up in case the H5N1 strain spread to humans.
In the UK, health authorities say they have begun modeling scenarios for an avian flu pandemic in response to the threat.
The World Health Organization (WHO) has described the situation in Cambodia as ‘worrying’ in a noticeable shift in rhetoric.
Earlier this month, the agency had assessed the threat of bird flu to humans as “low.” But the WHO says it may reconsider that status based on the latest update.
Dr. Sylvie Briand, WHO’s director for preparedness and prevention of epidemics and pandemics, told reporters they were considering the shift.
She said: ‘The global H5N1 situation is concerning given the widespread spread of the virus in birds around the world and the increasing reports of cases in mammals, including humans.’
Concerns about the transmission of bird flu to humans arose this month after cases also emerged in mammals, including minks and sea lions.
This brings the virus one step closer to infecting and spreading among humans.
Bird flu viruses usually have a harder time spreading in people because the mortality rate is so high and the infection can kill so quickly, meaning people die before they have a chance to pass it on.
Professor Francois Balloux wrote on Twitter this week that bird flu is a ‘serious concern’.
But he said that while human-to-human transmission is happening, it’s not happening any more than before at the moment, and “by far the most likely scenario for H5N1 is nothing happening at this point.”
Bird flu infections in humans are rare.
However, they can occur when enough virus gets into a person’s eyes, nose, or mouth or is inhaled.
People who have close or prolonged unprotected contact (not wearing respiratory and eye protection) with infected birds or in places where sick birds, their mucus, saliva or faeces are contaminated may be at greater risk of infection.
But it’s unlikely that a human can contract the virus from eating poultry or wild fowl because the disease is heat sensitive, meaning the meat won’t contain the virus as long as it’s cooked properly.
An infected bird may appear lethargic, stop eating, have swollen body parts, and cough and sneeze. Other birds may die suddenly without any symptoms.
The symptoms in humans are high fever (often above 30°C), cough, sore throat, muscle aches and a general feeling of malaise.
Additional early symptoms may include abdominal and chest pain and diarrhea.
It can quickly develop into a serious respiratory illness, including shortness of breath and difficulty breathing, and pneumonia. People can also suffer from altered mental status or seizures.