Although cases of bird flu are increasing among birds on commercial farms and in backyard flocks, transmission of avian flu to humans is very rare, and the risk to the public is very low

Virus illustration

A rare case of bird-to-human avian influenza has been reported in South West England.

The person acquired the infection from prolonged handling of a large number of infected birds kept around their home, the UK Health Security Agency (UKHSA) said.

Transmission of avian flu to humans is very rare, and the risk to the public is very low, the health protection body stressed.

H5N1 strain detected in routine monitoring 

The case was detected after the Animal and Plant Health Agency identified an outbreak of the H5N1 strain of avian flu in the individual’s flock during routine monitoring. All the birds infected have been culled.

The person in question was swabbed by UKHSA staff in line with precautionary procedures, and a laboratory analysis confirmed that the virus was the ‘H5’ type found in birds.

It has not yet been possible to confirm that the infected person has the H5N1 strain, but the World Health Organization has been notified, based on the available evidence.

It is the first human case of this strain in the UK, although there have been cases elsewhere globally, the UKHSA said, adding that the individual concerned was currently well and self-isolating.

All the person’s contacts, including those who visited the premises, have been traced, and there was no evidence of onward spread of the infection to anyone else, it said.

Dr Holly Shelton, Head of the Influenza Viruses Group at The Pirbright Institute, said: ‘A large infectious dose is required to infect a human with an avian influenza virus as there are significant barriers that the virus must overcome in order to establish infection.

‘Human-to-human transmission of H5N1 avian influenza viruses [is] extremely rare and there is nothing in the genetic makeup of the most recent H5N1 avian influenza strain reported in the UK that [suggests that] this virus would be capable of efficient and effective human-to-human transmission.’

Professor Isabel Oliver, UKHSA Chief Scientific Officer, commented: ‘Currently, there is no evidence that this strain detected in the UK can spread from person to person, but we know that viruses evolve all the time, and we continue to monitor the situation closely.’

Cases of bird flu increasing 

The UK’s Chief Veterinary Officer, Christine Middlemiss, said: ‘We are seeing a growing number of cases in birds on both commercial farms and in backyard flocks across the country.’

In the week leading up to Christmas, she warned that the UK was facing its largest ever outbreak of avian flu, with over 60 cases confirmed since the beginning of November.

Wild birds migrating to the UK from mainland Europe during the winter months can carry the disease, and this can lead to cases in poultry and other captive birds.

Last winter, between November and March, 26 cases of avian flu were confirmed in kept poultry and wild birds in the UK.

Avian flu in humans: symptoms and treatment 

The main symptoms of avian flu in humans are:

  • a very high temperature, or feeling hot or shivery
  • aching muscles
  • headache
  • a cough or shortness of breath.

The onset of symptoms can be very quick, according to the NHS, with pneumonia and acute respiratory distress syndrome listed among complications.

Treatment with antivirals may prevent complications and severe illness.

Professor Mike Tildesley, Professor in Infectious Disease Modelling at the University of Warwick, commented to the Science Media Centre: ‘This is clearly going to be big news, but the key thing is that human infections with H5N1 are really rare—fewer than 1000 worldwide since 2003—and they almost always occur as a result of direct, long-term contact with poultry.

‘It can result in a nasty infection for the individual concerned, but there has never been any evidence of sustained human-to-human transmission of H5N1, so at present I wouldn’t consider this to be a significant public health risk.’

This article originally appeared on Medscape, part of the Medscape Professional Network.

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Lead image: Kateryna_Kon/stock.adobe.com

Image 1: Kateryna_Kon/stock.adobe.com