Why did Native Americans die from European diseases while Europeans didn't catch serious diseases from the New World?

I've read that Africa contains populations of bacteria that have been co-evolving with our ancestors for tens of millions of years and are able to survive all of Homo Sapiens' immune systems' defenses as well as those of other primates. Most of these are harmless, but they form a reservoir of human-adapted germs from which new desease strains can come. Other regions including the Americas don't have any comparable source of new diseases that can infect humans.

Sorry, I don't have the source for this. If true, it would explain why few or no major human diseases have their origins in the Americas, which I believe was the original question.

Question:
Why did Native Americans die from European diseases while Europeans didn't catch serious diseases from the New World?

This question is covered in depth by Jared Diamond's excellent Pulitzer Prize winning book Guns Germs and Steel which describes broadly why European powers which came in contact with indigenous non Eurasian peoples around the world were so militarily sucessful. (North American Indians, Central America Aztecs, South American Inca's, Pacific Islands, South Africa are examples given in the book).

A big part of the European advantage over non Eurasian continent populations was their stronger germs. According to the book 95% of native populations were killed by European diseases (small pox, measles, plague(black death)) prior to colinization. Daimond attributes these "stronger European germs" to several factors.

• Europe's dense Populations, facilitated transfer and resistance to germs.
• The availability of large domesticated animals (horses, oxen, cattle ) living in close proximity to their population. Most other (no such large domesticated animals existed in the America's or Australian) continents did not have native large domesticated animals. (possible exception was Lama, but it's use was issolated.
• Eurasia is the longest continent, thus a greater land mass in a similar climate where germs incubate. Also similar climate also facilitates trade, immigration which move germs. Diamond makes the case that continents which are longer lattitudinal (North South) don't provide the same opprotunity for germ exchange.

These were the European advantages.

He mentions the tropical diseases (mainly malaria) that limited European penetration into Africa as an exception. Endemic infectious diseases were also barriers to European colonisation of Southeast Asia and New Guinea.

One of the biggest considerations, although hypothetical and not talked about, is simply the water. A great number of diseases and plauges during this era were due to waterborne pathogens. Europeans rarely drank plain water during the period, and you were more likely to find them drinking beer, wine, and mead just for this reason. It was commonly diluted into their water supplies as well, because the alcohol killed of the majority of the pathogens.

This is quite contrary to the newly explored western worlds natives at the time, who relied on the purity of their water. In short, it could be quite possible that Europeans introduced pathogens into their water supply that they had not had time to develop immunities to. This seems quite more plausable than other scenarios speculated about this subject. Early biological warfare.

Native Americans (and indigenous islanders) did not have many diseases on their side to use against the Europeans. Plagues spread quickly between people. Secondly, if you get a plague, either you die or you become immune. If you survive, you will never get it again, because now your body knows how to kill it. However, you can still carry the plague, and you can spread it to other people, but it can't hurt you.

The reason is that the New World didn't have plagues! But why didn't the New World get plagues?

Plagues prosper when you have a civilization/city which does a bad job of separating sewage from drinking water. This can help spread the plague, which helps evolve it fast. This makes deadly plagues. One such city which had bad water management was London. This made Cholera, one of the deadly diseases which haunted the Native Americans.

Cholera, and many other plagues, cannot survive in an isolated area. It will simply infect everyone, and then die because it does not have any more hosts available! The remaining living people will be immune, so the disease will die off. So, plagues need cities and highly connected trade routes to survive. China and India were great for plagues to live, because they had extremely high populations for most of history. In cities throughout Eurasia, people migrated, people were born, it was crowded, and that meant that the plague could spread indefinitely and prosper.

So, since the New World had less cities (and less population), it had less plagues. The New World could not ever be as advanced as the Old World (before Europeans) because they did not have the animals that we depend on. Pigs, horses, cows, elephants, and dogs were vital to the rise of humans, and they were not there in the New World. That meant that the New World had less cities, less population, less achievements, and less diseases.

However, the New World still had connections, and cities such as Tenochtitlan. The reason that there was no diseases coming from Native American cities is because the germs that cause the plagues don't want to kill you. Just like how the common cold lives in you and keep you alive, plagues want to keep you alive so it can live in you. The reason it kills you is because it thinks you are another animal, like, a cow. A germ in a cow, that does not kill it, accidentally traveled to a human. It does the stuff it does to a cow, and you die. Now it spreads to other humans. Now, lots of humans are dying and you have a plague.

This means that to have a plague, you must have as much contact with animals as possible. In the Old World, where farmers tended for cows and pigs, while warriors rode horses and elephants, there was a much higher chance of accidentally getting a disease from the animal that in the New World, where there was not as much contact between animals and humans.

This is what happened with the coronavirus, when a human came in contact with a bat disease. For a bat, COVID-19 will be easy to beat, just like the human cold. However, for humans, it can kill you.

So, the short answer? There were more animals to domesticate, so there were diseases hopping from animal to human. These diseases prospered in crowded, well traveled cities, and high human populations made more diseases. Also, bad water management and sanitation helped diseases spread. America did not have domesticatable animals (other than the llama) and less cities and less population, so there were naturally less diseases.

That said, there were some diseases that spread from America to Afro-Eurasia. Syphilis is a sexually transmitted disease that is believed to have originated from the Americas. However, most of the diseases did come from Eurasia.

There is one missing piece to this answer. The Vikings did come to the Americas far before Columbus, and it is likely that the [Mali Empire (Abubakari) also made it.] [1] There is a small chance that China (Zheng He) also made it to the Americas before Columbus.(2) So why didn't the natives get the plague from these early travelers and be immune to the Spanish? The reason is that, when the explorer landed on the coastal tribe, he would have spread the disease to them. However, the plague could not have spread to any other tribe due to lack of contact, and due to isolation. That one tribe would have died out, and the 5% that survived would be immune. This is kind of like social distancing. However, the disease would die out because it would have no one else to infect. That is why most of the Americas were vulnerable.

Check out this source: https://www.youtube.com/watch?v=JEYh5WACqEk

Hope this answers your question.

(1) http://moorishharem.com/the-battle-for-the-americas-mansa-abubakari-ii-181-years-before-columbus/, https://www.csu.edu/dosa/AAMRC/news1.htm , https://www.youtube.com/watch?v=vIUJtxPiCWE.

(2) https://www.1843magazine.com/travel/cartophilia/did-china-discover-america

If you get sick and bring your disease to the place you are going (for instance, because you were on a long and exhausting journey), you are going to be ill at your destination. You may have carried the germ for a long time, since you are used to it, and it will only strike if/when you are weakened.

If you get sick at your destination, it is not likely that you are allowed on board for the voyage back.

The only way a disease is going to make it back to your origin, is if it incubates longer than the time it takes you to board the ship and sail home, or if it incubates long enough to cause an infection spreading in the ship, but not wipe out the ships population.

Looking at the duration of the Atlantic voyage, this may pose serious constraints on the last scenario. More people are likely to get sick in the destination country. If only one party is traveling, this skews chances. Native Americans did not travel to Europe as far as I know.

Of course, travel over land is not isolated in the way a ship is and will have far fewer constraints.

I'd say the syphilis was was quite a deadly illness contacted from the Native Americans. They were immune to it (wonder if they still are…).

Although it is not 100 % historically proved that the syphilis originated from the New World, it started spreading like crazy after its discovery.

Certainly some diseases are of New World origin.

The Old World had more diseases and more deadly diseases simply because the population was much greater and in certain place more concentrated.

It is likely that more New World natives were killed by disease than by violence. However, this is just as true in the Old World: many more have died of disease than by war.

It is reasonable to assume Old World inhabitants have more developed immune systems, being in a more disease-intensive place, however as far as I know this is unproven. It is difficult to measure the "quality" of an immune system. Certainly, some people are more resistant to illness and others tend to be sickly, but the reasons for this are unclear.

There is a significant environmental aspect to illness. Tropical regions, for example, harbor many more diseases than temperate regions. Serious contagious illnesses are usually transported by a vector of some kind, so interaction with the vector may be more important than immune response.

Several good answers have already been suggested, but there are a few very important points that are worth mentioning: Native Americans were badly unprepared for the emergence of epidemic disease among their populations, both genetically and culturally.

According to this article from 2002, there was a major genetic component to it: far less immune system biodiversity among Native Americans than Old Worlders.

Indigenous biochemistry may also have played a role. The immune system constantly scans the body for molecules that it can recognize as foreign—molecules belonging to an invading virus, for instance. No one's immune system can identify all foreign presences. Roughly speaking, an individual's set of defensive tools is known as his MHC type. Because many bacteria and viruses mutate easily, they usually attack in the form of several slightly different strains. Pathogens win when MHC types miss some of the strains and the immune system is not stimulated to act. Most human groups contain many MHC types; a strain that slips by one person's defenses will be nailed by the defenses of the next. But, according to Francis L. Black, an epidemiologist at Yale University, Indians are characterized by unusually h*m*genous MHC types. One out of three South American Indians have similar MHC types; among Africans the corresponding figure is one in 200. The cause is a matter for Darwinian speculation, the effects less so.

It also points out that, when serious disease struck, Europeans knew how to handle it and Native Americans did not, which just made it worse for them:

Having little experience with epidemic diseases, Indians had no knowledge of how to combat them. In contrast, Europeans were well versed in the brutal logic of quarantine. They boarded up houses in which plague appeared and fled to the countryside. In Indian New England, Neal Salisbury, a historian at Smith College, wrote in Manitou and Providence (1982), family and friends gathered with the shaman at the sufferer's bedside to wait out the illness—a practice that "could only have served to spread the disease more rapidly."