Bird flu could also be mutating to develop into extra transmissible to people say scientists after girl caught first extreme case within the US

Bird flu could be mutating to become more transmissible to humans, scientists have warned, as the US reported its first severe case that left one woman hospitalised.

So far 65 confirmed human cases of H5N1 infection have been reported in 2024, following a widespread outbreak across bird and cattle farms in the United States.

A teenager in British Columbia, Canada, has also reportedly suffered severe symptoms and is being treated in hospital.

Experts believe the figure may be higher with instances going undetected among dairy and poultry workers.

In the latest case, a woman from Louisiana suffered severe respiratory symptoms and was in ‘critical condition’ after coming into contact with sick and dead birds, The Telegraph reports.

It is understood that she is older than 65 and had underlying health conditions, officials said earlier this month.

An analysis posted by the Centers for Disease Control and Prevention (CDC) on its website found a small percentage of the virus detected in the patient’s throat had genetic changes that may lead to ‘increased virus binding’ to specific ‘cell receptors found in the upper respiratory tract of humans.’ 

These changes have not been found in birds, including in the backyard poultry flock thought to have infected the Louisiana patient initially.

Bird flu could be mutating to become more transmissible to humans, scientists have warned. Pictured: Culling has begun at infected sites in the UK

So far 65 confirmed human cases of H5N1 infection have been reported in 2024, following a widespread outbreak across bird and cattle farms in the United States

The UK has also confirmed an outbreak of the virus, with 14 sites affected since November

The CDC stated that the mutations were ‘likely generated by replication of this virus in the patient with advanced disease,’ adding that no transmission of the mutated virus to other humans has been identified.

While the findings are ‘concerning’, the risk to the general public remains the same and is low.

The particular mutation ‘is one step that is needed to make a more efficiently transmissible virus,’ said Angela Rasmussen, a virologist at the University of Saskatchewan in Canada. ‘But I do want to point out that it’s not the only step.’

Michael Osterholm, a University of Minnesota infectious disease researcher, warned however that bird flu could in time become a major pandemic similar to coronavirus.

‘There will be additional influenza pandemics and they could be much worse than we saw with Covid,’ he told the Associated Press. ‘We know that the pandemic clock is ticking. We just don’t know what time it is.’

Bird flu has now become prevalent in multiple states across the US. 

California governor Gavin Newsom imposed a state of emergency on December 18, after the virus was found in at least 875 dairy herds in 16 states. 

The virus has also been detected in the UK. 

Culling of infected birds has begun in Britain, as experts attempt to stop the spread of the virus

Turkey farms were hit by an outbreak of bird flu just before Christmas.

Avian influenza has reportedly been found in 14 sites across Britain since November.

As a result, tens of thousands of Turkeys have been culled in a bid to control the outbreak, The Telegraph understands.

Eight of the infected sites are in Norfolk, including five turkey farms, one duck farm, one chicken farm and a non-commercial site home to emus and aviary birds.

It is thought the infected birds were humanely culled and the owners were compensated.