Interesting. Couple questions. What about disease transfer from Europeans to Asia and Africa? I guess precolonial exchange had already allowed mutual exposure to most disease vectors, except for ecologically isolated ones like malaria? You provide explanations for the lack of disease vectors in North and South America. But if, upon introduction to the Americas, smallpox could spread, then why couldn't similarly infectious viruses arise endogenously? I get the xoonotic argument, but it doesn't seem sufficient. Weren't the population densities of Mexican and South American cultures sufficient to support infectious vectors? Perhaps they did, and the dispersed, low-density population structure in North America was the result of previous epidemics?
Yeah, Africa, Asia, and Europe have been linked by trade routes for quite some time, so you ended up with isolated vectors like tsetse flies or mosquitos that caused problems. As far as why they couldn’t rise endogenous, their livestock like llamas just didn’t have things like Camelpox (evolutionary ancestor of smallpox) to contend with. There would’ve been some areas with sufficient density for spread, that’s for sure! As far as that last hypothesis you mention, future evidence could take us there but it would be overturning quite a bit, so I’m not expecting that finding anytime soon.
Interesting. Couple questions. What about disease transfer from Europeans to Asia and Africa? I guess precolonial exchange had already allowed mutual exposure to most disease vectors, except for ecologically isolated ones like malaria? You provide explanations for the lack of disease vectors in North and South America. But if, upon introduction to the Americas, smallpox could spread, then why couldn't similarly infectious viruses arise endogenously? I get the xoonotic argument, but it doesn't seem sufficient. Weren't the population densities of Mexican and South American cultures sufficient to support infectious vectors? Perhaps they did, and the dispersed, low-density population structure in North America was the result of previous epidemics?
Yeah, Africa, Asia, and Europe have been linked by trade routes for quite some time, so you ended up with isolated vectors like tsetse flies or mosquitos that caused problems. As far as why they couldn’t rise endogenous, their livestock like llamas just didn’t have things like Camelpox (evolutionary ancestor of smallpox) to contend with. There would’ve been some areas with sufficient density for spread, that’s for sure! As far as that last hypothesis you mention, future evidence could take us there but it would be overturning quite a bit, so I’m not expecting that finding anytime soon.