The birds are back in town. Spring migration could fuel spread, evolution of avian flu, scientists warn – CBC

Some birds migrate normally while infected, said biologist Andrew Lang, while others get ‘extremely’ sick

Apr 07, 2023

Across Canada, an estimated seven million birds and counting have been infected with highly pathogenic avian influenza (HPAI) during a devastating global outbreak that shows no signs of winding down.

The virus is also striking and killing other species, from farmed mink to wild sea lions to a domestic dog in Ontario, federal officials announced last week.

Now, with millions of birds crossing the continent and flying north to Canada in the months ahead, scientists warn it’s yet another opportunity for this virus to spread and evolve.

“It gives more opportunity for transmission,” said veterinarian Dr. Scott Weese, a professor at the Ontario Veterinary College. “And if we have birds coming from different areas where the virus has evolved differently, it creates more opportunities for this virus to change further.”

Canadian researchers are watching this year’s migration season closely. They aim to gauge how it impacts ongoing virus transmission, and to determine which species are being hit hardest by HPAI — and which ones are, somehow, beating the odds.

Read more: https://www.cbc.ca/news/health/avian-influenza-spread-evolution-1.6804656