The World Health Organization warned on Wednesday that a recent surge in bird flu outbreaks in mammals could help the virus spread more easily to humans.
Since late 2021, Europe has been hit by the worst outbreak of bird flu, while North and South America have also experienced severe outbreaks.
This led to the extinction of tens of millions of chickens worldwide, many with the H5N1 strain of the virus, which first emerged in 1996.
But there has been a recent worrying increase in infections in mammals.
“Avian influenza viruses typically spread among birds, but the increasing number of H5N1 avian influenza detections among mammals—which are more closely related to humans than birds—raises concern that the virus may be adapting to infect to people more quickly,” WHO said in a statement.
“In addition, some mammals can act as mixing vessels for influenza viruses, leading to the emergence of new viruses that can be more harmful to animals and humans.”
Outbreaks have been reported in 26 species, including farmed mink in Spain and seals in Chile. H5N1 was recently found in cats in Poland.
The WHO, along with the Food and Agriculture Organization (FAO) of the UN and the World Organization for Animal Health (WOAH), urge countries to work together to save animals and protect people.
“There has been a recent paradigm shift in the ecology and epidemiology of avian influenza that is raising global concern as the disease spreads to new geographical regions and causes unusual wild bird deaths. , and an alarming increase in mammalian cases,” said WOAH chief science officer Gregorio. Torres.
Infections in humans can cause severe disease with high mortality rates.
Cases of human bird flu are usually the result of direct or indirect exposure to infected live or dead poultry or a contaminated environment.
“The virus does not appear to be easily transmitted from one person to another, but vigilance is needed to detect any evolution of the virus that could change that,” said WHO’s pandemic preparedness chief. Sylvie Briand.
Experts are looking for changes that could put people at greater risk, and urged countries to improve their monitoring capabilities, he added.
“This is especially important because the virus is currently affecting countries with limited experience in avian-flu surveillance,” Briand said.
Harmful spread of birds
The WHO says that since 2020, a variant has led to an “unprecedented” number of deaths in wild birds and poultry in many countries in Africa, Asia and Europe.
The virus spread to North America in 2021 and then to Central and South America in 2022.
Last year, 67 countries on five continents reported highly pathogenic H5N1 bird flu outbreaks, with more than 131 million domestic poultry lost due to death or destruction in affected farms and villages.
By 2023, another 14 countries had reported outbreaks, mostly in the Americas, as the disease continued to spread.
These epidemics have caused “devastation” of chickens and damaged the livelihoods of farmers and food traders, the WHO said.
“Several mortality events have been reported in wild birds,” the UN health agency added.
“Although most affect animals, these outbreaks pose a constant risk to humans,” it said.
“The epidemiology of H5N1 continues to evolve rapidly,” said FAO chief veterinary officer Keith Sumption.
He pleaded for the timely sharing of genetic sequences to monitor changes, resulting in better risk assessment and disease control.
© 2023 AFP
Citation: WHO worries bird flu could adapt to humans ‘quicker’ (2023, July 13) retrieved on 13 July 2023 from https://phys.org/news/2023-07-bird-flu- humans-easily.html
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