Bird flu, also known as avian flu, is an infectious type of influenza that primarily spreads among birds. While most strains of bird flu do not infect humans, there are four strains that have caused concern in recent years:
- H5N1 (since 1997)
- H7N9 (since 2013)
- H5N6 (since 2014)
- H5N8 (since 2016)
Although these strains don’t easily infect people and aren’t usually transmitted from human to human, there have been cases of human infection worldwide, leading to fatalities. In February 2021, H5N8 was found to have infected a small number of people in Russia for the first time
