There is genetic evidence discussed in Hopkins’ “Princes and Peasants: Smallpox in History,” which implies ancient existence of variola viruses, as you note from the Wiki article. The newer paper overstates the case in typical academic fashion in order to sound as noteworthy as possible. The issue with saying that earlier emergence is not the “current” disease of smallpox is that we expect significant evolution to occur once there is sufficient population density, and more once there is selection pressure due to vaccination, and so it is very unsurprising that there are more recent changes. (I discuss this in my most recent paper, https://www.liebertpub.com/doi/pdf/10.1089/hs.2018.0039 )
It’s very clear that a precursor disease existed in humans for quite a while. It’s also very clear that these outbreaks in thin populations would have continued spreading, so I’m unconvinced that the supposed evidence of lack due to Hippocrate’s omission, and the lack of discussion in the old and new testament is meaningful. And regarding the old testament, at least, the books aren’t great with describing “plagues” in detail, and there are plenty of times we hear about some unspecified type of plague or malady as divine punishment.
So the answer depends on definitions. It’s unclear that there is anything like a smallpox epidemic as the disease currently occurs in a population that is not concentrated enough for significant person-to-person spread. If that’s required, we have no really ancient diseases, because we defined them away.
Curious if you could explain molecular clock analysis like I’m five? Your argument here sounds plausible but I’d still be interested to get a better handle on that.
I’m definitely not the best person to explain this, since I’m more on the epidemiology side. I understand the molecular clock analyses a bit, and they involve mutation rates plus tracking mutations in different variants, and figuring out how long it should take for the various samples collected at different times to have diverged, and what their common ancestors are.
Classical antiquity definitely has plagues in the modern sense, like the Antonine plague. Indeed, in your paper you endorse the fairly standard claim that it was smallpox. That seems to me worth mentioning here, more than the negative claim about Hippocrates.
But to clarify, I don’t think the Antonine plague is quite the same as modern ones, for the simple reason that it could only spread over a fairly limited geographic region, and it could not become endemic because of population density constraints. Smallpox evolution is driven by selection pressure in humans, and the “500 years old” claim is about that evolution, not about whether it affected humans at any time in the past. That said, it absolutely matters, because if the original source of smallpox was only 500 years ago, where did it come from?
The question is how smallpox evolved, and what variant was present prior to the 1500s. It’s plausible that Horsepox, which was probably the source for the vaccine strain, or Cowpox, spread via intermediate infections in cats, were the source—but these are phylogenetically distant enough that, from my limited understanding, it’s clearly implausible that it first infected humans and turned into modern smallpox at recently as the 1500s. (But perhaps this is exactly the claim of the paper. I’m unclear.) Instead, my understanding is that there must have been some other conduit, and it seems very likely that it’s related to a historically much earlier human pox virus—thousands of years, not hundreds.
There is genetic evidence discussed in Hopkins’ “Princes and Peasants: Smallpox in History,” which implies ancient existence of variola viruses, as you note from the Wiki article. The newer paper overstates the case in typical academic fashion in order to sound as noteworthy as possible. The issue with saying that earlier emergence is not the “current” disease of smallpox is that we expect significant evolution to occur once there is sufficient population density, and more once there is selection pressure due to vaccination, and so it is very unsurprising that there are more recent changes. (I discuss this in my most recent paper, https://www.liebertpub.com/doi/pdf/10.1089/hs.2018.0039 )
It’s very clear that a precursor disease existed in humans for quite a while. It’s also very clear that these outbreaks in thin populations would have continued spreading, so I’m unconvinced that the supposed evidence of lack due to Hippocrate’s omission, and the lack of discussion in the old and new testament is meaningful. And regarding the old testament, at least, the books aren’t great with describing “plagues” in detail, and there are plenty of times we hear about some unspecified type of plague or malady as divine punishment.
So the answer depends on definitions. It’s unclear that there is anything like a smallpox epidemic as the disease currently occurs in a population that is not concentrated enough for significant person-to-person spread. If that’s required, we have no really ancient diseases, because we defined them away.
Thanks!
Curious if you could explain molecular clock analysis like I’m five? Your argument here sounds plausible but I’d still be interested to get a better handle on that.
I’m definitely not the best person to explain this, since I’m more on the epidemiology side. I understand the molecular clock analyses a bit, and they involve mutation rates plus tracking mutations in different variants, and figuring out how long it should take for the various samples collected at different times to have diverged, and what their common ancestors are.
By “really ancient” you mean bronze age, right?
Classical antiquity definitely has plagues in the modern sense, like the Antonine plague. Indeed, in your paper you endorse the fairly standard claim that it was smallpox. That seems to me worth mentioning here, more than the negative claim about Hippocrates.
Yes.
But to clarify, I don’t think the Antonine plague is quite the same as modern ones, for the simple reason that it could only spread over a fairly limited geographic region, and it could not become endemic because of population density constraints. Smallpox evolution is driven by selection pressure in humans, and the “500 years old” claim is about that evolution, not about whether it affected humans at any time in the past. That said, it absolutely matters, because if the original source of smallpox was only 500 years ago, where did it come from?
The question is how smallpox evolved, and what variant was present prior to the 1500s. It’s plausible that Horsepox, which was probably the source for the vaccine strain, or Cowpox, spread via intermediate infections in cats, were the source—but these are phylogenetically distant enough that, from my limited understanding, it’s clearly implausible that it first infected humans and turned into modern smallpox at recently as the 1500s. (But perhaps this is exactly the claim of the paper. I’m unclear.) Instead, my understanding is that there must have been some other conduit, and it seems very likely that it’s related to a historically much earlier human pox virus—thousands of years, not hundreds.