Experts have expressed concern about how far across the world bird flu is spreading and say its spread should be closely monitored.

Avian influenza has been detected as far away as South America and the virus has also killed mammals such as sea lions, mink, foxes and otters.

It is infecting wild bird populations across the globe and could potentially infect some species, perhaps even endangered ones, that have never before been in contact with the flu, creating uncertainty about how they will react to the virus.

Professor Ian Brown, head of virology at the Animal and Plant Health Agency (APHA), told a virtual Science Media Centre press briefing: “I think it is really quite a worry that the virus has already reached so far down into South America.

“And we have to consider that there are definitely risks for biodiversity in terms of Antarctica.”

Professor Martin Beer, head of the Institute of Diagnostic Virology at the Friedrich Loeffler Institute in Germany, said: “And this is a point which is also worrying me most at the moment that it’s reaching areas where this type of virus has never been.

“And we are talking about a whole continent with a lot of different bird species which never had contact with this kind of virus.”

The virus has been detected in North and South America and so far only Africa and Australia have been spared.

Prof Brown said it is important to closely monitor the spread of bird flu, and mutations in the virus, and learn lessons from the Covid-19 pandemic.

He added: “Have we got good systems that are globally set up to track and monitor those concerning events fast?

“If this virus was to ever, heaven forbid, jump to humans, we need to have done that basic work in the animal and bird sector.

“So it is about global responsiveness here and working together globally to make sure we can track this virus very fast and understand what it’s doing.

“My biggest concern is have we got that global structure… have we learnt all the lessons from Covid?”