Bird flu (H5N1) is a strain of influenza that has, until recently, primarily affected birds. Transmission from birds directly to humans has been known to occur, but not human-to-human transmission. This is a relief, because the fatality rate from bird flu has apparently been up at 56%.
Since October 2021, bird flu had been spreading more and more throughout bird populations; the BBC has reported at least 42 million birds are thought to have died from the virus, and another 166 million have been culled as part of viral control efforts. So much poultry had to be euthanased and destroyed as a result of the virus that it pushed up chicken prices in some countries, like I think the USA. The virus has also increasingly come to affect migratory birds, which is worrying, because of course they then spread the virus to all-new territories on their journeys.
As of February 2023, it’s being reported that bird flu is now being transmitted mammal-to-mammal. For example, the virus has been observed spreading between minks at a farm in Spain, affecting multiple wild animals in Colorado, and at least 585 sea lions have been killed by the virus in Peru. A lion at a Peruvian zoo has also died. In the UK, otters and foxes have also contracted bird flu; it’s believed they ate carcasses of infected birds. They did have a variant of the virus that makes mammal-to-mammal transmission easier, but as yet the UK doesn’t think that’s happened in their country. On 11 February, Ecuador reported its first known case in a human (a 9yo girl). The US had apparently had its first human case for this outbreak the previous April.
See Also / References
- Tweet by Zeynep Tufekci screenshotting a NYT article (4 Feb 2023)
- Tweet by BNO News about sea lion deaths in Peru (8 Feb 2023)
- BBC News: Bird flu ‘spills over’ to otters and foxes in UK (9 Feb 2023)
- The Denver Post: Bird flu infects Colorado mountain lion, black bear and skunk, all now dead (9 Feb 2023)
- Reuters: Ecuador confirms first human bird flu infection in 9-year-old girl (11 Feb 2023)