Why bird flu threat is rising and what can be done about it

The most recent outbreak of avian influenza (AI), starting in October 2021, broke records for the greatest number of cases seen – not only in the UK, but most of Europe.

Sporadic cases of the disease are still emerging now, despite poultry flocks ranging again. While the mandatory avian influenza prevention zone (AIPZ) was recently lifted, the ever-present threat makes maximising biosecurity on poultry farms no less critical.

See also: Avian influenza prevention tips and how to handle an outbreak

“Another outbreak of this scale is likely to happen again,” warns vet Kenny Nutting, director at St David’s Poultry Team.

“We are all generally of the opinion that because we are seeing positive farms in summer, it could potentially be worse this coming autumn, winter and spring.”

Dr Nutting has overseen logistics for the recent AI outbreak, running site visits and post-mortems to determine AI presence across the UK.

What the numbers tell us

Since the beginning of the outbreak there have been 109 confirmed captive poultry AI cases in England, 11 in Scotland, five in Wales, and six in Northern Ireland, according to Defra.

This compares with 26 cases of AI in captive birds in the UK’s previous outbreak between November 2020 and March 2021.

“In a normal year, there are between five and 20 cases, so to get 110-120 cases this year is a significant rise,” says Dr Nutting. “There have been more than 15,000 wild bird positives found in various different areas. This shows us the amount of virus that is in our environment.

“Commercial bird culls are probably in the late hundreds of thousands to early millions,” adds Dr Nutting. “And still seeing positive farms in the middle of a summer heatwave is particularly worrying.”

Millions of pounds will have been lost through meat birds being culled instead of sold, loss of egg production, or offspring. There was also a reduction in exports under the World Organisation for Animal Health regulations because of bird flu status in certain areas.

Then there are the hidden costs of logistics and licensing to move animals, extra biosecurity and getting secondary shed cleansing and disinfection. Additional labour has also been needed to keep up with biosecurity requirements and to process suspected AI reports.

Free-range poultry businesses struggled with an unprecedented long housing order period from 29 November 2021 to 2 May 2022. “Every county in England, Scotland and Wales has had wild birds with bird flu identified, which is significant in showing the spread,” says Dr Nutting.

Why has this AI outbreak been so bad?

In previous years, there have been three or four strains of bird flu, but this year there was one highly pathogenic avian influenza strain, H5N1, which caught hold.

As cases are still being seen, it is likely that the next housing order will be put in place sooner than before, as the virus still seems to be present.

Weather has also affected cases. Ten days after storm Eunice in February 2022, the virus spread rapidly. “Hotspots of disease were seen in Yorkshire, the Suffolk/Norfolk border, Hereford, Leominster and Warwickshire. Unsurprisingly, there are more cases in areas with more farms.”

Viruses seem to be becoming more resilient; in South Africa and western Europe bird flu has been seen throughout the summer months, says Dr Nutting. “We have certainly seen fewer harsh winters, so is the milder winter allowing the virus to replicate and survive better? This could be an effect of global warming.”

What we can learn for the future

It is easy to become complacent about biosecurity, but this outbreak has been a reminder of why it is so important. The quality of biosecurity expected by many farm assurance auditors in the UK is needed to reduce risks such as avian influenza.

“This bird flu situation is exactly why we have high biosecurity measures – to avoid the disease spreading like it has in other countries,” says Dr Nutting.

“Another learning point from this outbreak is that it’s important for farmers to be proactive in calling the vet or Defra if they hear that bird flu is close to their farm,” says Dr Nutting.

“Know what kind of licences you may or may not need if you fall into a bird flu zone.” As with many sectors, staff shortages can delay processing of AI outbreak calls, so giving Defra time to process licences and vet visits will help speed up action.

Poultry farmers who own 50-plus birds must be on Defra’s poultry register by law. “It is impossible to get a licence to move your produce if you’re not on the register,” adds Dr Nutting.