By The Telegraph (World News) | Created at 2024-11-21 17:15:10 | Updated at 2024-11-24 15:15:49
2 days ago
Europe is ramping up monitoring for human cases of H5N1 avian influenza ahead of the winter flu season over fears of virus reassortment, health officials have said.
New guidelines from the European Centre for Disease Prevention and Control (ECDC) aim to ensure rapid detection of cases, including updates to testing protocols and symptom criteria.
“We are monitoring very closely because reassortment could occur,” Dr Angeliki Melidou, principal expert in respiratory viruses at the ECDC, told The Telegraph.
Reassortment—the mixing of genetic material between seasonal flu and animal flu-like H5N1—is more likely in winter, as flu cases surge.
This raises the risk of poultry and farm workers contracting both viruses and creating a new, more transmissible strain. The 2009 swine flu pandemic resulted from the same process.
According to modelling by Airfinity, a health data analytics company, the risk of H5N1 reassorting this winter will increase by five-fold compared with the summer months.
While no human cases of H5N1 have been reported in Europe, more than 50 have been detected in the US this year, raising concerns the virus may be better adapted to infecting humans.
Since 2020, hundreds of thousands of H5N1 cases have been reported in animals - like poultry, foxes, mink, seals, and even dolphins, across Europe, providing ample opportunities for spillover into humans.
As recently as September, thousands of wild and domestic birds located on the coasts of the Atlantic Ocean, North Sea, and Baltic Sea have tested positive for H5N1.
The ECDC’s updated guidance points to symptoms seen in recent North American cases, including milder cases where the only symptoms are conjunctivitis.
“We’ve updated our guidance to include milder symptoms in individuals exposed to birds or other animals,” Dr Melidou said. “The priority is to strengthen surveillance and ensure we monitor and follow up with exposed individuals.”
Healthcare workers across Europe are now advised to ask patients with flu-like symptoms about recent contact with birds or other animals – a shift from standard influenza protocols.
The threshold for H5N1 testing has also been lowered to include individuals without known animal exposure, following cases in the US and Canada where infections occurred with no clear link to farmed animals.
Samples of any suspected cases should also now be sent to national influenza labs for sequencing, and any positive cases will be told to self-isolate.
The UK Health Security Agency (UKHSA), the agency responsible for managing pandemic risks in Britain, has not issued any new guidance on bird flu for clinicians over the winter season.
The last update for medical professionals in regards to identifying avian influenzas was published in February 2024, before the US reported its first case.
“We cannot exclude the possibility of H5N1 triggering a human pandemic,” Dr Melidou said. “It has many opportunities to adapt as it expands its host range, so vigilance is crucial.”
The ECDC still considers the risk of a member of the general public catching H5N1 bird flu to be low. For people who work with animals, the risk is low to moderate.
The risk assessment could change if epidemiologists start to see clusters of human cases in the US, which would suggest the virus is now able to spread between humans, Dr Melidou said.
She added that if the cases in the US become more severe - almost all of the 50 confirmed cases so far have had exceedingly mild illnesses - the ECDC might reconsider their assessment.
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