H5N1 bird flu detected in pig for the first time in the US

The mammals are described as effective ‘mixing vessels’ for influenza because they have receptors for both avian and human flu viruses

H5N1 bird flu has been detected in a pig in the US for the first time, sparking concern that the virus could become better at infecting and spreading between humans.
The animal was found in a backyard farm in the US state of Oregon that was also home to H5N1-infected poultry, the US Department for Agriculture (USDA) said on Wednesday.
The livestock and poultry on the farm reportedly shared water sources, housing and equipment, and at least two other pigs on the property have been tested for bird flu and scientists are awaiting the results.
Although H5N1 is not new – it was first detected in the 1990s – the virus has spread rapidly in wild bird populations since 2020.
It has recently been found in a wide range of mammals, ranging from foxes to seals and polar bears, and has more recently jumped into cattle farms in the US.
The latest finding of the virus in pigs is something experts have warned over for months.
Pigs were the source of the H1N1 pandemic – also known as ‘swine flu’ – and have been implicated as the source of other influenza outbreaks.
The mammals have been described as “mixing vessels” for influenza because they have receptors for both avian and human flu viruses, allowing them to be infected by strains from different species at the same time.
When this happens, the viruses can exchange genetic material in a process known as “reassortment” which can make it more likely that the virus could adapt to spread between humans.
“If this virus starts transmitting in pigs, that absolutely increases the risk [of a pandemic],” Richard Webby, a St. Jude Children’s Research Hospital virologist who studies flu in animals and birds for the World Health Organization, told Reuters. 
The development comes as the USDA is set to begin bulk testing raw milk supplies across the country for bird flu as surveillance efforts ramp up.
Although the Food Standards Authority (FDA) has assured the public that the country’s pasteurised milk is safe, they have stressed people should avoid the raw variety over fears they could become infected with H5N1.
The agency will begin sampling milk in affected states in early November, followed by states where no infected dairy cattle have been affected.
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