The World Health Organisation on Wednesday expressed concern that one of the world's worst outbreaks of avian influenza on record could develop into a health threat against humans.
There have been increasing reports of deadly cases of avian flu, also known as bird flu, among wild birds and poultry globally, leading to some fatal outbreaks among mammals.
The developments are causing alarm that the virus with a high mortality rate could be passed from mammals to humans.
“Avian influenza viruses normally spread among birds, but the increasing number of H5N1 avian influenza detections among mammals – which are biologically closer to humans than birds are – raises concern that the virus might adapt to infect humans more easily,” the WHO said in its statement.
“In addition, some mammals may act as mixing vessels for influenza viruses, leading to the emergence of new viruses that could be more harmful to animals and humans.”
At least eight known H5N1 cases of infected humans have been reported since late 2021 but they have been among people who interacted with sickened birds, which is rare.
The World Organisation for Animal Health said at least 131 million birds including poultry have died – either by widespread culling or mass death – in 2022 and so far this year.
The WOAH said that it received reports of influenza outbreaks in sea and land mammals, including cats and dogs, in at least three continents but warned there may be outbreaks that have not yet been detected.
“There is a recent paradigm change in the ecology and epidemiology of avian influenza, which has heightened global concern as the disease spread to new geographical regions and caused unusual wild bird die-offs, and alarming rise in mammalian cases,” said Dr Gregorio Torres of the WOAH.
The WHO says studies are being undertaken to investigate the possibility of changes in the virus causing these mammal outbreaks, and any threat to humans.
The agency, alongside the WOAH and the UN's Food and Agriculture Organisation, called on countries to “save as many animals as possible and protect people”.
The three organisations are also advising that governments increase monitoring of the avian flu.
“This is especially important as the virus is now affecting countries with limited prior experience in avian flu surveillance,” they said.
