All of them.
The HxNx virus’s are merely routine genetic iterations that cycle through the avian population and ultimately the swine population in Southern China.
The parasite cycle is not interrupted due to the unclean and uncontrolled practices of pig raising operations there.
The CDC has a team that I believe lives there and collects as many samples as they can to figure out which mutation is dominant for that year. That’s where they get the candidate flu vaccines for each season.
So the question is this...if we didn’t have mass immigration from China to our country, or Europe, would we ever see these viruses?
Probably we would, but it would be greatly attenuated, since it would be flareups in small areas.
Anyway, you can do a search on “HxNx virus” and read all about it. It’s well known in virology, and of course unmentionable in politics because God Forbid we should limit Chinese colonization.
https://en.wikipedia.org/wiki/Influenza_A_virus_subtype_H5N1
Wow! I had no idea.
I wonder if maybe they were kicked out once things got really nasty?