We’ve all heard about how the Europeans brought all kinds of horrible diseases over and killed off a lot of the Native American population. However, it seems to me that there should have been some nasty bugs over here that the newcomers did not have resistance to.
I find references to the Columbian Exchange, but nobody indicates whether the New World bugs had any effect. So I appeal to the group mind - anyone have anything on this?
It’s theorized that syphilis came to Europe from the New World. The timing was about right and it certainly acted like a disease to which people have no previous exposure.
All the indigenous people of the Americas were were descended from a few small groups of nomadic hunters who crossed over from Asia relatively recently. There probably weren’t enough of them to carry anything really lethal along with them, and they hadn’t been here long enough for a lot of new diseases to evolve.
Contrast that with Europe that has been settled by humans for far longer and has been in continuous contact with Africa where the various bugs have had hundreds of thousands of years to perfect feeding on humans. It’s not surprising that the nasty deadly things mostly flowed one way.
People living in densely packed cities have more exposure and resistance to germs. During the Civil War Northern troops got sick less frequently than Southern ones.
It’s also theorized that syphilis was not a New World disease (news story about medieval syphilitic skeletons).
The Americas did and do have some endemic diseases like Chagas disease and Carrion’s disease, but they just don’t travel all that well as they are tied to particular insect vectors that for whatever reason are a little less vagile than critters like the Aedes mosquitos.
The other point to note is that many of our really nasty diseases come from our domestic livestock. Influenza comes from pigs and ducks, smallpox comes from cows and so forth. The Indians lacked much in the way of livestock. Turkeys, cavies, llamas, dogs and that’s about it. The scope for infection with zoonotic pathogens was severely limited. As a result here were simply fewer diseases available for them to infect the rest of the world with.
[hijack]Smallpox is host adapted to humans (and can experimentally infect some primates). You may be thinking of cowpox (or monkeypox), which IS zoonotic, although it causes a less severe infection than smallpox (and infection with cowpox is protective for smallpox). In fact, since smallpox can only naturally infect humans, that was key for its eradication (no wildlife reservoirs).
Most of the seasonal influenzas are also host-adapted to humans, and most influenzas in birds are host-adapted to birds. The influenzas in birds tend to bind to different cellular receptors than the mammalian influenzas.
Turkeys in the new world could have had their own low pathogenic avian influenzas (heck, migratory birds between the New and Old World have been around for a long time), but those may not have crossed over to humans.
There are zoonotic animal diseases, but those are not the two best examples. After all, Trypanosoma cruzi and different Leishmania spp. are zoonotic protozoal parasites that are native to the New World and cause plenty of diseases in humans (and probably cause disease in pre-Columbian times).
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Do you have a source for this?
How the Dope has changed. It’s taken 10 posts for someone to mention Guns, Germs, and Steel? For Clothahump, that’s a book by Jared Diamond in which he attempts to explain why it was Europe that overran the Americas rather than the other way around. He engages in a lengthy discussion about why Old World diseases wiped out Native Americans rather than New World diseases wiping out Europeans.
Executive summary: humans evolved in the old world, alongside domestic animals and pathogenic microbes, and we all had a long time to evolve with each other. Native Americans were essentially free from all these old diseases, and became immunologically naive. Meanwhile, they hadn’t been in the Americas long enough for new diseases to emerge and adapt to humans. This was exacerbated by the fact that there were few to no good domesticatable animals in the Americas, as Diamond states that many of our diseases first emerged as a consequence of close association with other large mammals.