Thank you. If they've been doing it forever, why is it just now making not only them but everyone else in the world sick?
Probably a rhetorical question. Regardless, gives me the opportunity to vent regarding the malpractice-at-a-global-level China commits by not shutting these sh!thole markets down.
Ease of transportation is clearly why the diseases are getting to the rest of the world more easily. Increased population density in China overall, but especially the increased density due to urbanization, is bringing the wet markets in closer and more frequent contact with people.
Wet markets, if they contain the magic trifecta of birds/bats, pigs, and humans, are the witches cauldron that keep spinning up these diseases. Benign viruses jump from the bats/birds into pigs and then into humans (where they are no longer benign).
Zoonotic diseases are very common, both in the United States and around the world. Scientists estimate that more than 6 out of every 10 known infectious diseases in people can be spread from animals, and 3 out of every 4 new or emerging infectious diseases in people come from animals. Because of this, CDC works 24/7 to protect people from zoonotic diseases in the United States and around the world.
From:
www.cdc.gov
Same dynamic in Africa, but more or less substitute "monkeys" for "pigs" as the intermediate agent/vessel. Population density is less in Africa (as is ease of transportation out of Africa), so outbreaks tend not to take off like they do out of China.
--- Ed of line (MCP)