After reports of an outbreak of highly pathogenic avian influenza (HPAI) in minks from a farm in Spain, further updates from the UK reveal that the virus has been detected in other mammals. An article by the BBC in February 2023 explained that although this “spill over” event was concerning, the risk to the public is still said to be “very low”.  

Otters and foxes 

The BBC reports that the latest figures suggest H5N1 has led to the death of “about 208 million birds around the world” and has been identified in “at least 200 recorded cases in mammals”. International reporting has shown infection in grizzly bears in America, minks in Spain, and dolphins and seals.  

Further surveillance will be carried out, but the Animal and Plant Health Agency (APHA) has tested 66 mammals, including seals. It found that 9 otters and foxes were positive for HPAI H5N1. They are suspected to have preyed on infected wild birds.  

Despite these increasing reports, UKHSA continues to advise that avian flu is a bird disease.  APHA emphasises that there is a “very low likelihood of any widespread infection in GB mammals”. However, experts are investigating the infections to understand the risk of spill over.  

Further investigation 

Professor Ian Brown is APHA’s Director of Scientific Services. He told the BBC that “a sick or a dead wild bird contains an awful lot of virus”. Thus, mammals that find and consume these birds will be “exposed to very large quantities of virus”, allowing the virus to enter a “host population that it doesn’t normally maintain in”. 

Professor Brown stated that the UK’s national avian flu taskforce was increasing surveillance of cases and genome analysis of the virus. 

“The virus is absolutely on the march. And it’s almost remarkable – it’s a single strain.”  

He called on the international community to tackle the spread collaboratively, as he is “acutely aware of the risks” of another pandemic. The spread is “a concern” and necessitates “new strategies” such as “international partnerships”.  

“If we don’t solve the problem across the globe, we’re going to continue to have that risk.” 

Previous cases 

In 2022 we reported that restrictions had been lifted in the UK, resulting in farmers calling for bird vaccination strategies to be implemented to protect their stocks. DEFRA and APHA advise that there have been 166 confirmed cases of HPAI H5N1 in the UK since 1st October 2022 , with 279 cases in England since October 2021.  

We will hear more about strategies against avian influenza at the World Vaccine Congress in Washington 2023. Join us by getting your tickets here.