November 18, 2014

expert reaction to identification of bird flu on Yorkshire duck farm as H5N8

The strain responsible for the outbreak of avian flu on a duck farm in Yorkshire has been identified as H5N8.

Dr Holly Shelton, The Avian Viral Diseases Programme, The Pirbright Institute, said:

“A detailed look at the virus at the molecular level indicates that it is even less likely than H5N1 to infect people.

“H5N8 avian influenza virus has been confirmed as the causative agent of the outbreaks in Yorkshire UK and is likely related to the H5N8 outbreaks in the Utrecht province of the Netherlands and in Mecklenburg–Western Pomerania in Germany. Genetic information gathered from the viruses of the Dutch and German outbreaks are the same as the strains that caused severe outbreaks in birds in South Korea, China and Japan early in 2014. By looking at the genetic information of the viruses that are similar to the virus causing the H5N8 outbreak in the UK, so those in Germany and South Korea, scientists have determined that there are no signatures in any of the virus genes that indicate this virus would be able to efficiently infect humans.

“Influenza virus researchers have for years been investigating the characteristics and genetic signatures required for an influenza virus to infect humans and become transmissible between them and so we know what indicators to look for. Analysis of the H5N8 viral surface protein, HA, which allows for attachment and entry of the virus into cells (the first important step in infection), has been characterised as preferentially binding the bird receptor, little of which is found in the upper respiratory tract of humans. This contrasts with the situation for H7N9 which has caused disease in humans in China over the past year and some isolates of the notorious H5N1 in South East Asia where the virus surface protein is capable of efficiently binding to the human receptor, increasing the likelihood of human infection by the H7N9 and H5N1 viruses. Therefore the risk to humans of the H5N8 looks minimal with our current knowledge; once full genetic information about these viruses in the UK is available a more detailed risk assessment can be undertaken.”

Prof Andrew Easton, Professor of Virology, University of Warwick, said:

“The identification of this strain as H5N8 increases the likelihood that it is linked with the outbreaks in Germany and the Netherlands. This will be the subject of further investigations to try to confirm the link by genetic analysis of the virus. The finding that it is H5N8, which has not been associated with infection of humans or other species, means that the threat to humans remains very low.”

https://www.gov.uk/government/news/avian-flu-outbreak-in-duck-breeding-farm-in-yorkshire

Declared interests

None declared