Everything I’ve read says that most of the Native Americans died out due to the crop of diseases that Old Worlders brought over that Native Americans had no resistance to. And that many of these diseases came from livestock that the Europeans owned and interacted with.
So let’s say that America did have domesticated livestock, and built up a resistance to more diseases. Would this have helped the Native Americans, or would their strain of diseases have been different enough that they weren’t resistant to European diseases, or even further, would spread their unique diseases to the colonizing Europeans?
It kind of depends. If they had similar population densities as Europe or Asia, with similarly sized cities, they’d also have some nasty diseases. Really, it’s not the presence of lifestock, per se, but having tons of people in close, regular contact with each other and with animals, which magnifies the chance of a disease mutation jumping species. Also, trade routes made it easier to spread disease, which was a bit harder in the Americas, as there are some deserts and mountains that get in the way.
Had the American aboriginals larger population densities, regular contact with animals, and easier trade routes from north to south, there very well could have been cross contamination and massive disease outbreaks between them and the Europeans once travel was established between the continents. Neither would have had immunity to disease strains from the other since diseases would have developed independently, limiting the ability to develop immunity.
I think it depends heavily on to what extent the new animals did or did not match the old world animals. If they had common old world animals like pigs, cows, and horses, it would probably not make much difference. If we are talking about entirely new species, or species that have been isolated so long as to evolve very different diseases, it could be quite dangerous for the Europeans.
Estimates for initial mortality following 1492 go up to 90%. These have been established by archaeologists, epidemiologists and others using multiple lines of evidence. Even taking a very conservative 50% mortality , then many areas where small populations were only recorded at contact would have had the big settlements, and most likely the long distance integrated trading networks that took bugs across the continents.
Most human deaths would come directly from human diseases circulating in better protected old world populations. animal diseases may have jumped, but can’t think of any with known grat impact in say period to 1550. The impact results from both the severity of individual diseases, and the succession of different diseases. The ability of populations to maintain cultural continuity and cohesion in the face of aggression will be compromised rapidly as different age groups become vulnerable.
Worth noting that the Aztec state and the Crown of Castile were roughly the same size and arguably had roughly similar populations ( or possibly much higher in the Aztec case, depending on which figure you accept ). If anything Castile was larger with a lower population density. Tenochtitlán was also one of the world’s largest cities at the time, again varying with which numbers you like.
An outlier for the Americas as a whole, but there were certainly urban areas and dense-ish populations to be found here and there.
I’ve said before - I remember reading a review of a book about the smallpox epidemics that hit the villages of the upper northwest coast natives - the Indians and Inuit of BC and Alaska. The gist was that the actual mortality rate from an unfamiliar disease was no worse than for Europeans. What did them in was lack of “herd immunity” and a subsistence lifestyle. The disease would strike almost everyon at the same time; with nobody to feed or bring water to the sick, most people died from the aggravating factors of dehydration, starvation, and exposure during the fever. Where there was a missionary or previously exposed resident that had already had the disease, mortality rates were lower. In some places care of the sick meant that smallpox mortality was only about 10%, same as in Europe.
This is indicative of another issue. Epidemics did not necessarily “sweep the continent”. Where there were larger populations and a lot of intercommunication, diseases would spread easily. This I assume explains the disappearance of the huge Mississippi cities that existed before Columbus. But in more isolated areas, a tribe or an area might acquire a disease on contact with Europeans, and mainly die off, without passing the disease further on into the area.
I should also point out that one theory says that the flu, for example, is bred in the pigsties of southeast Asia; mixes of bird bacteria and pig bacteria generate various interesting diseases. Birds fly everywhere. So presumably some components of diseases are world-wide. Some components are local.
Isn’t another factor said to be not only did they not have prior exposure, but because of their isolation they did not have much genetic diversity, hence the lack of variation in MHC meant what killed one would kill most of them?
But this is the opposite of what I read - that diverse large populations of Europeans, or Africans, or Asians - all have approximately 10% mortality rate if they get smallpox, just as North American natives did if properly cared for during the fever.
the difference was that in a large, interconnected society in Europe there would always be a number of people who had previously had the disease (or cowpox) and had a decent supply of stored food to provide for the sick; and epidemics were frequent enough in Europe that you did not get 90% to 100% of a village or town sick at the same time.
There was a large Indian population with many cities in the region of what is now Northern Florida, Georgia, Alabama, Mississippi, and Arkansas that was visited by Hernando de Soto’s expedition of 1539 - 1542. Many native communities were devastated by disease after his passing.
I think the Wikipedia article is fairly accurate. The peak of the Mississippian cultures had passed before Columbus arrived. But they continued in somewhat reduced circumstances until other Europeans began exploring…
The article I remember was a review of a book doing a scientific study of the BC and Alaska epidemics. It dug into government statistics and first person reports of missionaries and traders. More likely to be accurate.
perhaps a more telling result would be how fast the natives fell ill. That would be an indication of a badly adapted immune system. An exhibit in the Victoria Museum included (includes?) stories of the entire canoe-load of natives (they had BIG canoes) all falling ill at once while trying to paddle home from Victoria in the late 1800’s.
I believe it’s the opposite - much like AIDS, (and Black Death when it first hit in 1348, and the Spanish Flu in 1918) the initial burst of the disease is wide and deadly. Then mortality peters out, and while the early AIDS victims died in a year or less, some people now survive decades. that can’t all be due to drugs. One theory is that the most virulent strains kill their victims too fast and die out once the danger is perceived, while the less virulent allow their victims to linger and pass on the disease, until what was a ruthless killer becomes an occasional danger.
De Soto also brought pigs with him to help feed his expedition. nothing like adding to the disease risk. (Pig body chemistry is very close to human, so we are very susceptible to their diseases.