antonknee:

 

Zoonotic (animal to human) transmission is downright scary. I know its not a popular opinion, but the way humanity treats and uses animals is a recipe for disaster - factory farming, wild animal markets, etc etc. Think about a lot of the recent scares (SARS, H1N1, bird flu, MERS, Covid) which are all zoonotic in origin, and something like 75% of emerging infectious diseases are zoonotic in origin.

 

True, but the very worst risk is probably not directly from usual domestic farmed livestock that we've been living alongside for millennia and sharing contagious diseases with, but new diseases that we've never been exposed to through either wild food from species we've never had much contact with but either food shortages makes us hunt them, or we move into their habitat because we're running out of places to live or farm, or habitat destruction means the animals move to where we are, or a worse risk:

It looks like Covid in humans may have originated not from a "wild" intermediate vector, but an intensely farmed species - could be pangolins or bamboo rats or something else - that became infected from the original source - assumed to be bats.  Zoonoses generally aren't initially well-adapted to infect other species, and those species which may have acted as an intermediate host probably living not in their natural environment with relatively sparse density, but grouped together. When the first bamboo rat got infected then it probably wasn't easily transmitted between them, but the unusual / artificial high density means it's more likely to jump from host to host, add humans to the mix (probably tending those animals) and once it's jumped to us and jumps back and forth, the chance of it adapting to become what it is - a highly contagious human disease is high.

Not saying that farming the animals we do for food (ie in NZ) is a perfectly safe idea, but it's much safer than large scale commercial farming of exotic species that still have contact with their wild relatives, and that live with and are in constant contact with humans.

If there's a TLDR, then it's probably "there are too many people on the planet".