Felines and mankind have been residing in harmony for many years but that hasn't always been the situation. There were times when felines have been practically wiped out in the name of God. And what occurred the Black Death reigned supreme for considerably longer than it should. So we will go back to the beginnings of recorded history to enough time of the pharaohs of Egypt. Here pet cats were revered as Gods and many were mummified to last for eternity. As the felines guarded the grain warehouses and killed the rats and mice that fed on the grain. Therefore lowering famines, that were the curse of Egypt. It was illegal to destroy cats in those days, like cows in India today.
If this attitude towards cats dates back generations then one can realize why historians say the Black color Death started in China. Where there are rats and no cats then the rats dominate and that would have been a precursor for the disease to get close to people. Now once i go back to China you may still find rats running around however, not so many in the casing estates. There are several down by the river. Also they have a very efficient rubbish clean up system that helps to keep the places very clean. Where I stay the rubbish is gathered everyday. That could also keep the rat inhabitants down. And with so many discarded pet cats playing around the rats don't possess much of a chance. I've never seen this but I think the government accumulates a lot of cats. There used to be colonies of stray cats surviving in some places but now I don't see them any longer.
I think one of the reason why there were not many cats around is because they used to eat them. And once in a while the restaurant feline catches would grab an cat they could find and take them back to the restaurant. I recall seeing felines in glass exhibits out the front of the restaurants. But somewhere between then and now they forbidden eating pet cats. So cats are actually not on the menu and now there are pet cats everywhere. Many of them started off in someone's house and received thrown away, as most are incredibly friendly. Also they may have this thing about abdominal worms. And in those days China had not been as modern as now so abdomen worms is a problem. Fleas are not really a problem because they may have tile flooring and wooden furniture.