No, it was the neolithic, and in particular animal husbandry that was the culprit rather than simply urbanization which was a later emergence. And when you contrast new world peoples who had very few animals to domesticate, there's only one disease thought to have originated there: syphilis. This is despite the records of highly concentrated populations in various regions in the New World.
"In the world our human immune system evolved in hundreds of thousands of
years ago, infectious diseases could not become a major problem because, with a
few exceptions, when you survive an infectious disease, you usually don’t get it
again. Either it kills you or it leaves you completely immune to it for the rest of
your life. For the vast majority of human history our species lived in small tribes
that were spread thin and, for all intents and purposes, pretty isolated from each
other. An infectious disease simply could not become a dangerous threat and
establish itself in our ancestors effectively. Because if it infected a tribe, it would
infect every available person in no time and then die off because there would be
no one left to jump over. So our evolution did not really have to consider these
sorts of pathogens that much.
"As we became farmers and city dwellers our lifestyle changed forever—and
so did the diseases that targeted us. Living close together created a perfect
breeding ground for infectious diseases. Suddenly, in evolutionary terms, there
were hundreds or even thousands of victims to infect. As our ancestors were not
aware of the nature of microorganisms or even basic hygiene and they did not
yet possess tools like soap and indoor plumbing, there was not much they could
do—on the contrary, their lack of understanding made things worse.
"And when they began domesticating and living together with animals in
close quarters, often even sleeping in the same rooms, some pathogens jumped
over. Our new lifestyle turned out to be the perfect environment for the
pathogens of our new animal friends, to adapt to humans and vice versa. As a
consequence, virtually every infectious disease we know today arose in the last
ten thousand years. From cholera, smallpox, measles, influenza, and the
common cold to chicken pox."
Our immune systems were evolving 100 thousand years ago, and they still are now.
If we weren't able to handle new diseases, everyone would have died from covid, not some percent of a percent. Our immune systems are very very capable for handling pathogens
So does Guns, Germs, and Steel and Sapiens, and Dawn of Everything and so does 1491 - and for all they do touch on disease what I've said comports with them.
