by Started in the midst of the covid-19 pandemic, the current avian flu epidemic is already treated by scientists as the largest in the history of Europe. A new variant of the virus, called avian influenza A (H5N1), emerged in 2020. Since then, it has affected not only wild birds, but also some species of mammals, such as minks, badgers, pigs and bears.
There are several types of avian flu that can infect birds. One of them, H5N1, appeared in 1997 and, in the last two decades, around 850 infections in humans were registered. Although the number is considered small, about half of those infected died.
Regarding the avian influenza A (H5N1) variant, there are records of at least ten cases in humans and one death. In animals, 6,615 cases were recorded in 37 countries between October 2021 and October 2022.
Since last October, researchers have observed a total of 2,701 infections in animals.
Will H5N1 cause the next pandemic?
This new variant of H5N1 has a mortality rate of 50% and, therefore, public health authorities are concerned. This rate is higher than that of other viruses that have caused recent flu epidemics, such as the H1N1 swine flu in 2009.
Scientists say that if this new strain finds a way to spread efficiently among humans, the result could be catastrophic. But so far, researchers say the likelihood of that happening is still very low.
According to Richard Pebody, head of the High Threat Pathogens Group at the World Health Organization (WHO) Europe, all people who have tested positive for this new variant of avian flu have had close contact with wild birds.
“These people work with poultry and were involved in the slaughter [de aves] or had contact with flocks in an outdoor area”, summarizes Pebody.
This suggests that the risk of contracting the virus is greater for those who have close contact with sick birds.
Risk of spreading between humans
For the H5N1 variant of bird flu to spread widely, it would have to adapt to the ability to easily infect humans. And, so far, there is no evidence to indicate that she has found a way to do this.
But researchers have expressed some concern that the virus is starting to spread among other mammals.
In October 2022, a major outbreak occurred on a farm with 52,000 minks in Galicia, Spain. Experts who analyzed the phenomenon said it is possible that the virus spread among the animals themselves.
The researchers said, however, that it is difficult to identify exactly how the virus spread, as it is difficult to determine whether all minks had been exposed to the disease through some food, for example, or whether the virus, in fact, spread between animals – or even a mixture of these two possibilities.
Adaptation of H5N1 in mammals is a warning sign
According to Pebody, the spread of the virus among minks is a warning sign. “Humans are mammals too. So if the virus suggests a mammalian adaptation – its ability to propagate in a mammalian host – that is just one step closer to having more attractive biological characteristics for propagation between humans,” he adds.
Scientists closely monitor all major outbreaks of the virus among mammals to understand how it is spreading and evolving. This month, authorities reported an outbreak in Peru, where thousands of sea lions – up to 3% of the entire population – had died of H5N1.
Therefore, researchers seek to identify any potential spread of the virus among the animals themselves.
Birds frequently get the flu, but the H5N1 variant has been especially deadly. Researchers estimate that more than 60 million wild birds died from the virus or from a cull last year – when a single bird contracts the virus, breeders are forced to kill the entire flock.
how to protect yourself
For those who do not work in direct contact with birds, the best way to protect yourself, according to Peabody, is to avoid catching birds on the street. Still, according to the expert, the risk is low.
“It’s important to note that millions of birds have died and we’re only seeing a small number of cases in humans, so right now the risk remains relatively low. But there is a risk,” says Pebody.
He adds that anyone who works in poultry or has chickens or roosters in their backyard should wear protective gear when handling the animals.
According to the WHO, the incubation period after an infection with avian influenza A (H5N1) is two to five days, on average, but symptoms can take up to 17 days to appear.
According to Pebody, a vaccine for humans is already being developed by researchers.
If you have had contact with dead or sick birds and develop respiratory symptoms, contact your doctor and local health authorities, get tested and seek advice on antiviral treatment.
