No increased risk to human health from H5N1 bird flu in poultry

03-01 | |
Since 1 October 2022 there have been 130 confirmed cases of avian influenza in England. Photo: Jan-Willem Schouten
Since 1 October 2022 there have been 130 confirmed cases of avian influenza in England. Photo: Jan-Willem Schouten

UK health officials have found no increasing risk of the threat of the Eurasian H5N1 avian flu strain to human health following a detailed assessment. But they have stressed that the level of confidence is low and the situation requires regular review because of the ongoing high level of poultry transmission.

The Health Security Agency’s (HSA) assessment said available surveillance data reported by the Animal and Plant Health Agency (APHA) did not suggest widespread mammalian adaptation to the virus. However, there is evidence of direct spill over from birds into some “scavenger” wild species such as foxes and otters.

So far, there have been 4 instances of H5N1 detection in humans – 2 in Spain, 1 in the UK and 1 in the US. The assessment defined 6 levels of transmission to gauge the threat, putting the UK at level 3, meaning evidence of virus genetic changes that provide an advantage for adaptation to mammals.

Confirmed cases

Since 1 October 2022, the start of the current 2022/3 seasonal period, there have been 130 confirmed cases in England, along with detecting the H5N1 virus in 447 wild birds from 280 locations. Numbers of cases in poultry flocks have fallen in recent weeks.

James Mottershead, National Farmers’ Union poultry board chair, said it had been encouraging to see a fall in recent weeks. He welcomed the message from the UK’s chief veterinary officer, Christine Middlemiss, that this is partly attributed to good on-farm biosecurity.

In his end-of-year round-up, Mottershead said: “I am pleased that our collective efforts have been recognised by Christine Middlemiss and her team. Despite this encouraging picture in recent weeks, it is still devastating that in England, we have now reached the same number of AI cases between October and December 2022 as recorded throughout the previous 2021/22 outbreak year.”

Vaccination against bird flu

The NFU has been pushing for greater progress on AI vaccination and Mottershead said a cross-government and industry task force is due to meet in the early part of 2023. This will examine the current barriers to vaccination and how these may be overcome.

Government and the NFU continue to meet regularly: A fifth in a series of AI roundtable meetings was held shortly before Christmas, hosted by Lord Benyon and attended by environment secretary, Mark Spencer. Deputy chief veterinary officer, Richard Irvine, provided an update on the plateauing of bird flu cases in recent weeks but warned there could be a second peak in the next few weeks.

APHA chief executive, David Holdsworth, provided an update on compensation payments and the redeployment of vets from directly dealing with infected premises to completing work within surveillance zones.

Tony Mcdougal Freelance Journalist