Avian influenza poses a growing pandemic threat as the virus becomes more adaptive to humans, pets and zoo animals, European disease and food agencies warned on Wednesday, the 29th of January, while calling on countries to step up surveillance and containment measures to prevent the virus from evolving further and endangering humans, reports Politico.
“In 2024, avian influenza viruses expanded their range, infecting previously uninfected species. We have identified key mutations associated with possible spread to humans, which require rapid detection and response,” Bernhard Url, Acting Executive Director of the European Food Safety Authority (EFSA), said in a press release.
In recent years, avian influenza has been reported in large numbers in wild birds and farmed species such as chickens.
Lithuania reported on Wednesday an outbreak of bird flu on a laying hen farm in the western part of the country, where 20 000 of 246 387 birds died and all the remaining birds were culled.
During this time, the virus has also spread to other species, including seals and, particularly in the USA, dairy cattle.
However, the number of human cases has so far been low. The UK reported its first case this year on Monday, while the US has recorded 67 cases and one death.
The risk of infection remains low for the European population as a whole, but low to medium for people who regularly come into contact with potentially infected animals.
But the situation would change if “human-to-human transmission is confirmed”, said Edoardo Colzani, head of the respiratory viruses unit at the European Centre for Disease Prevention and Control (ECDC).
And the risk is increasing. The ECDC and EFSA have identified 34 key genetic mutations in the virus that increase the likelihood of transmission from animals to humans, as well as its ability to replicate to spread between humans.
The fact that the virus now has all these characteristics is a “sporadic event”, said EFSA Senior Scientific Officer Alessandro Broglia in an interview with Politico. Out of 27 000 samples of the virus, 144 were able to spread between humans, mainly in Asia and Africa, not in Europe.
However, both high- and low-pathogenic viruses can develop these features, and low-pathogenic viruses, which do not cause very serious diseases, can spread and mutate slowly over time, Broglia explained.
Monitoring these viruses is a “cornerstone” for detecting mutations that could make them dangerous to humans, he said.
Bird flu viruses can adapt to mammals by mutating or mixing with other viruses. Close contact between wild animals, poultry, livestock and humans increases the risk of the virus spreading.
“Are we creating the conditions for this to happen? What kind of poultry production system are we using? Why are there so many outbreaks on poultry farms in certain areas? And why are there so many outbreaks in mammals?” Broglia asked, urging countries to think about how human activity contributes to the spread of such viruses.
Nearly 100 people were infected last year, mainly through contact with sick animals in the workplace, said ECDC’s Kolzani.
He recommended that people should be tested when there is an outbreak among animals, even if they do not show any symptoms, to detect any hidden spread of infection.
To avoid the “extremely rare” case of human flu mixing with avian flu, Kolzani recommends vaccinating professional livestock farmers against human seasonal flu to help reduce this risk.
Avian influenza circulates globally, and while there are data from North America, Japan and South Korea, many regions lack data due to limited laboratory capacity.
“We know very little, if anything, about the rest of Asia or the whole continent of Africa, and that’s the problem,” said Broglia, “we have no idea what’s going on there.”
He stressed the need to step up research in these areas and to standardise genetic data, calling it “essential for prevention and preparedness”.