What do dead sea lions on the beaches of Peru, minks on farms in Spain, otters and foxes in the U.K. and dead grizzly bears in the U.S. have in common? Avian flu, otherwise known as bird flu. Along with thousands of pelicans, various migratory birds, and millions of domestic chickens, turkeys, and ducks, this recurring virus has killed, it has now managed to spread into a variety of mammals as well and is posing a potential threat to humans.
H5N1 first appeared in 1997 in China and killed millions of birds throughout Asia, Europe and Africa directly with millions more culled to prevent further spread. In 2022 alone there were over 50 million chickens culled in the U.S. and 5 million in Canada. However, the threat to humans has been low with only 1,000 people to date who have been infected, but more than half of them died with a mortality rate of around 60% or roughly 10 x that of COVID. Another strain, H7N9 also first appearing in China in 2013 and since then another 1,000 people have become infected with about the same mortality rate. The good thing is that avian flu does not appear yet to spread from human to human but rather from working with infected birds in the slaughter and plucking process. For the other mammals who died it was likely because they ate an infected bird.
However, with a mink to mink transmission of H5N1, the first among mammals, what is worrying health officials is the development of a human to human version of avian flu. Particularly in Asia, where the conditions there have humans, swine and poultry often in close proximity to one another, and able to infect one another, which could lead to a mixture of a pathogens that could create a human avian influenza. Recent research into the genes of the 1918 Spanish flu, which infected a third of the world population and killed 50 million or more people, indicate it was also a strain of both human and avian genes.