UK reports unprecedented jump in early season bird flu cases

U.K. authorities reported an unprecedented jump in early season cases of avian flu in both domestic and wild birds, triggering tight restrictions on poultry farmers across the country.

The government has confirmed 40 outbreaks of avian flu among poultry and other captive birds this year, resulting in the culling of about 500,000 birds, Chief Veterinary Officer Christine Middlemiss said Thursday. There were 24 outbreaks during the entire 2020-21 bird flu season, which ran through the spring.

"I'm very concerned about what's happening," Middlemiss told the BBC. "That's a really high number for the time of year for anything we've experienced before, and that's because of the high level of infection in the migratory wild birds. So it's really, really concerning because those birds will stay with us over the winter until early spring and the risk of infection remains."

U.K. authorities keep a close eye on avian flu cases around the world because it is spread by migrating birds and can be devastating to poultry producers. Experts estimate that outbreaks during the 2014-15 and 2016-17 seasons cost U.K. poultry producers about 125 million pounds ($165 million).

While the risk to humans is low, bird flu can affect people in rare cases.

To control the spread of the disease, poultry producers must kill all birds at sites where infections are confirmed. In addition, they have been ordered to keep all birds inside or under nets to stop them from coming in contact with wild fowl, and to implement strict hygiene measures.

While the number of birds culled so far this season sounds large, it is relatively small compared with the number of birds on U.K. poultry farms. Between the beginning of August and the end of October, poultry producers slaughtered about 20 million birds a week, according to the latest government statistics.

"In terms of food supply impact, it's actually a relatively small number," Middlemiss said of flu-related culling.

The situation in Britain is part of a larger trend across Europe, where authorities are seeing more frequent outbreaks of avian flu, Middlemiss said.

Although researchers don't know the reasons for the trend, one theory is that climate change has altered the migration patterns of wild birds, she said.

"The birds migrate to the north of Russia over the summer and mix with other birds and other global flight pathways there and they exchange the viruses, so it's quite plausible that with climate change and change in pathways different mixing is going on," Middlemiss said. "But that hasn't been fully investigated yet."

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