Outbreaks of bird flu have multiplied nearly fivefold last year, creating an urgent need for research to prevent the spread of the disease, according to the head of a new consortium investigating the virus.
The record 26 outbreaks involving H5N1 in 2021 has been broken, with 121 outbreaks with the H5 serotype this year, according to Professor Ian Brown, head of virology at the government’s Animal and Plant Health Agency (APHA).
This may be due to the growing number of people keeping chickens or ducks, Brown said. Many of these caregivers do not have to register with any authority due to the small number of birds involved.
“A good percentage of our cases have been in that kind of environment,” Brown said. “They’re on large commercial farms to someone who has two chickens in the backyard. So that’s a massive shift in terms of food safety risk, public health risk, animal welfare and poultry exports. corral “.
The Apha consortium was set up by the Department of Environment, Food and Rural Affairs (Defra) at breakneck speed after last year’s outbreaks caused alarm and disruption among poultry farmers and the first flu case. bird that infected a human in the UK.
“Over the last 10 years, we’ve had a number of bird flu events in the UK, but their frequency has been increasing,” Brown said. “Instead of coming every three or four years, it seems like we have an event every year and … they’re on a bigger scale.”
The risk to humans remains very low. Since the bird flu broke out 20 years ago, there have been about 600 cases worldwide, with no person-to-person transmission.
But the Covid pandemic has highlighted the risks of other potential zoonotic diseases, which are transmitted to humans by animals. “The more humans are in uncontrolled contact with birds, the greater the theoretical risk of people becoming infected,” Brown said, adding that the UK has “very good surveillance” for viruses. “If we can reduce the burden on birds, this will also have a beneficial effect on reducing the risk to humans.”
Avian flu is spreading to farm birds from the wild, and researchers are examining data collected over the past winter to find out what practices make farms less vulnerable to infection. When the last winter’s wave began, the government ordered that all birds be kept indoors, known in agriculture as “housing” rather than blocking, which meant that the eggs of free-range were not available in Britain for five weeks.
Bird flu has recently killed thousands of gannets in the UK. Photo: Danny Lawson / PA
The virus moves between birds through close contact: “It’s a droplet transmission, a bit like Covid,” Brown said. Bird droppings and nasal secretions are other vectors. Infectious feces from wild birds when they fly over farms can be part of the problem. “Even at 4ºC, the virus will survive happily, infectiously, for about eight weeks,” he added.
Another area of research is how and why wild birds get sick: the disease is very distressing to animals and often deadly. Thousands of birds have died in Scotland, most of them nesting in close-knit colonies, as well as gulls and seagulls.
“This is a concern because some of them are endangered and defenseless against the virus. When these birds come to breed in the summer, they get very close to each other. So snowballs pass through these colonies.”
Wild bird migration is probably another factor, and some of the largest mixes occur in Central Asian countries, such as Kazakhstan, in an avian version of the Silk Road.
The virus usually disappears from Europe in the summer, but this did not happen last year. He also came to North America only for the second time. Few birds cross the Atlantic, so it is likely that the viruses spread to the birds that spent the summer in the Arctic, which raises questions about whether climate change in the far north is also affecting the spread.