How did the bird flu virus become more deadly and persistent?
Core argument: A Nature study published October 18th found that in 2020 the bird flu virus spread among wild birds three times faster than among farmed poultry, attributing the gap to mutations that let the virus adapt to diverse species.
The study, published in Nature on October 18th, looked at changes to the virus’s genome over time and used data on reported outbreaks to track how it spread. In 2020, the rate of spread among wild birds was three times faster than that in farmed poultry, because of mutations that allowed the virus to adapt to diverse species. Outbreaks are usually seasonal, synchronizing with bird migration in Northern Hemisphere autumn. But since November 2021, they have become persistent. In 2022, the virus killed millions of birds across five continents and seeded outbreaks among farmed mink and various marine mammals.



