‘We don’t know what’s going to happen this year,’ admits expert of bird flu

Since 2021 bird flu has wreaked havoc with the European poultry sector.

Approximately 2,500 cases of Avian Influenza (A.I.) were detected on farms across 37 European countries between October 2021 and September 2022. The UK was hit especially hard, particularly with free-range flocks bearing the brunt of infectious cases.

Richard Jackson, a former British Veterinary Poultry Association president spoke recently in Cavan about the lessons learned from the period.

“Since October 2022 we’ve had 179 cases of AI in Britain. As we’re in the East Atlantic flyway which covers all the way from Canada, to Russia and down to South Africa we get a lot of wild birds. This was a worldwide issue, with cases all over the world in places like Kazakhstan, Japan, Chile and Argentina.”

He said that usually bird flu rates peak before dying off; but recently there has been no let-up in cases.

“Normally the migratory birds land and bring bird flu with them and when they go it disappears. In 2022 it stayed over the summer and never went away. We don’t know what’s going to happen this year.

“In the autumn of 2021, there weren’t a lot of cases. Then it spiked a bit in the spring of 2022, and trickled away during the summer before all hell broke loose in the autumn/winter of 2022. We were having several cases reported every day. It has slowed down since, but we don’t know if it will stay that way.

“In the peak of bird flu, there wasn’t a corner of the UK that wasn’t impacted, but it was particularly high in East Anglia where there are a lot of free-range ducks, turkeys and broilers, but there are also a lot of free-range pigs. The seagulls moved inland in the winter, stole the pig feed and as they did that they defecated and spread the disease.

“Unlike in Ireland, there is a lot of straw bedding for ducks and they need to be bedded every day, and a lot of them were stored in non-bio secure sheds and this was believed to be one of the reasons it spread as there were lots of cases here.”

Nobody really knows

Despite the cases reaching historically high levels Richard says it has been difficult to establish the root cause due to the relentless nature of the disease.

“Everyone wants to know why it got so bad last year, but nobody really knows. Normally government scientists investigate bird flu after the season ends, but there wasn’t a proper lull in cases to determine what particular features of the virus caused it to be such a problem.”

However, he said they were able to examine some aspects of the virus.

“We looked at the survivability of the virus in the environment, but this strain didn’t survive any longer than previous versions. They typically last for 50 days, and so did this one. We were able to see if it took less amount of virus to infect the birds, but the science showed it was the same amount.

“A lot of UK farmers wanted to blame the airborne spreading of the disease, but the science doesn’t back this up, it only spreads 10 metres in the air and 50 meters in feathers. In many units with AI, it didn’t spread quickly between sheds, it took weeks in some cases to move around the units.”

Wild birds

He said initial signs showed there was no spreading of the disease between farms.

“This means it was spread from wild birds. There are several ways this can happen from it being walked onto the farm, contaminated bedding, or leaking roofs.”

The UK government introduced several measures, such as an avian influenza prevention zone to prevent the spread of the disease.

“That made introducing biosecure measures a legal requirement. It means you keep waterfowl separate from chickens and turkeys; you must use a government-approved disinfectant at an approved rate, because some farmers were using unofficial sprays that were ineffective, and farmers had to keep a visitor’s record.

“All of these things should be done anyway, but this made it a legal requirement.”

Richard noted that in the UK the poultry sector is faced with a paradox.

“One of the issues in the poultry sector is we don’t know what good practises look like, because everyone is in agreement that bio-security is the major control for bird flu. Unlike in the cattle and sheep sector we can’t have farm walks to show good practices for bio-security reasons.”