Scientists are already talking about the largest avian influenza pandemic in European history. And it started at the same time as COVID-19. There are different types of avian influenza that can infect birds. One of them is called avian flu H5N1. It first appeared in 1997 and has infected about 850 people over the past two decades. Although this is a very small number, half of those infected have died.
A new lineage of viruses called avian flu A (H5N1) emerged in 2020. Since then, it has spread not only to wild bird populations, but also to specific species of mammals such as mink, grayling, pigs and bears.
Fewer than 10 people have been documented to be infected with this specific strain, and at least one person has died.
Between the beginning of October 2021 and the beginning of October 2022, authorities have detected 6,615 cases in animals in 37 countries.
This year alone, since October 2022, researchers have observed a total of 2,701 cases.
Will H5N1 cause another human pandemic?
This strain of bird flu has a 50% mortality rate and is considered a cause for concern by public health officials.
H5N1 has a higher death rate than other viruses that have caused recent flu pandemics, including the 2009 H1N1 swine flu pandemic.
Researchers say that if this new lineage of H5N1 were to find a way to efficiently spread between humans, the impact could be catastrophic.
But at this point, experts say the risk of that happening is very low.
All of the people who tested positive for the new avian flu lineage had close contact with wild birds, said Richard Peabody, head of the high-risk pathogen team at WHO/Europe (World Health Organization).
“They’re either working on the chicken farm and involved in slaughtering the sheep or interacting with the flock in the backyard,” Peabody said.
This suggests that if you do not have close contact with sick birds, you are safer than humans.
How does avian influenza spread in the human community?
For avian flu H5N1 to spread more widely among the general population, it would have to adapt to its ability to spread easily to humans. And, so far, there is no evidence to indicate that this lineage of H5N1 has found a way to do so.
But researchers have expressed some concern that the virus may be spreading to other, non-human mammals.
In October 2022, a large outbreak occurred on a farm in Galicia, Spain, with 52,000 minks. Researchers investigating that outbreak said the virus likely spread among minks.
However, researchers said it is difficult to identify exactly how the virus spread. They said whether or not all the minks were exposed to the virus through a food source, for example, or whether the virus spread among minks — or a mix of the two possibilities.
Mammalian adaptation of H5N1 is a ‘red flag’
Peabody said evidence of the virus spreading among minks would present a “red flag.” […] That the virus is changing in ways that are more worrisome.”
“Man is also a mammal,” he added. “So, if the virus is showing some suggestion of mammalian adaptation — the ability to spread in a mammalian host — it’s one step closer to having biological characteristics. [would] Make it more attractive to spread it to the human population.”
Scientists are closely watching all major outbreaks of the virus in mammals to see how it is spreading and evolving.
In March 2023, officials reported an outbreak in Peru, where thousands of sea lions—up to 3% of the population—had died from H5N1.
Researchers are trying to identify any possible sea lion-to-sea lion spread of the virus.
Sick birds also mean higher food prices
Birds often get influenza, but the H5N1 strain has been particularly deadly. Researchers estimate that more than 60 million wild birds have died in the past year from viruses or bacteria.
When a single bird in a flock has the virus, farmers must cull the entire flock.
And fewer farm birds mean fewer chickens in stores and markets. The recent outbreak among birds has contributed to higher egg prices in the US and may lead to higher chicken prices in general in the coming months.
How to protect yourself from avian influenza
Peabody said the best way for people to protect themselves — if they don’t have to work in direct contact with birds — is to avoid picking up birds on the street. But the risk, Peabody said, is still low.
“It’s important to highlight that millions of birds have died and we’re only seeing a small number of human cases,” Peabody said. “So, the risk is relatively low right now. But there is still a risk.”
Peabody added that people who work on poultry farms or raise chickens or chickens in the backyard should wear personal protective equipment when handling the animals.
According to the WHO, the incubation period after infection with avian influenza A (H5N1) is on average between 2 and 5 days, but it can take up to 17 days before we see symptoms.
Researchers are developing a vaccine for humans, Peabody said.
If you have been in contact with dead or sick birds and have developed respiratory symptoms, you should contact your doctor and local health authorities, get tested and seek advice about antiviral treatment.