I’m not an expert, but I don’t think that a single individual, or even a small team, could do that.
The genetic variety created and maintained by sexual reproduction pretty much ensures that no single infection mechanism is effective on all individuals: key components such as the cell surface proteins and the immune system show a large phenotypic variability even among people of common ancestry living in a small geographic region (that’s also the reason why finding compatible organs for transplants is difficult).
Even for the most infectious pathogens, there is always a sizeable part of the population that is completely or partially immune.
In order to create an artificial pathogen capable of infecting and killing everybody, you have to engineer multiple redundant infection mechanisms tailored to every relevant phenotipic variation, including the rare ones. Even if your pathogen kills 99.99% of human population, far more than any natural pathogen ever did, there would be 700,000 people left, more than enough to repopulate the planet.
Even for the most infectious pathogens, there is always a sizeable part of the population that is completely or partially immune.
Is this actually true? Of course, few diseases would actually have good odds of infecting everyone, but surely that’s more a matter of exposure. [EDIT: or how you define “partial immunity”.]
By “partial immunity” I mean that you catch the disease, but only in attenuated form, maybe even subclinical or asymptomatic, and usually develop full immunity afterwards. This happened even with higly infectious diseases such as the medieval Black Death (Yersinia pestis), malaria, smallpox, and now happens with HIV.
AFAIK, a superbug capable of infecting and killing everyone doesn’t seem to be biologically plausible, at least without extensive genetic engineering.
Tetanus doesn’t grant immunity if you actually get it and survive. They are soil/intestinal bacteria normally and they don’t grow within you to a high enough number that your immune system can get a good look at them, their toxin is just potent enough that even at low concentrations it kills you.
There are also protist pathogens which express vast quantities of a particular coat protein on their surface such that when you form an adaptive immune response agains them it is almost certainly against that protein—and something like one in 10^9 cell divisions their DNA rearranges such that they start expressing a different coat protein and evade the last immune response that their host managed to raise, resetting back to no immunity.
However, it was my understanding that not all natural diseases grant immunity to survivors. I’m not an expert, of course.
I’ve been led to understand that this was usually the other way around, or that the mechanism that allowed their survival in the first place was “change something in the immune system, see if it works, repeat until it does”. Through some magical process of biology or chemistry afterwards, the found solution is then “remembered” and ready to be deployed again if the disease returns. I’m not quite sure whether anyone understands the exact mechanism behind this magic, but I certainly don’t (yet). *
By “the other way around”, I mean a selection effect; they survived because they were already more resistant and had the right biological configuration ready to become immune to it or somesuch. I’m not clear on the details, this is all second-hand (but from people who knew what they were talking about, or so it seemed at the time).
* ETA:Gotcurious. Looks like there’s a pretty good understanding of the matter in the field after all. +1 esteem for immunology and +0.2 for scientific medicine in general. And those are some really great wikipedia articles.
I’ve been led to understand that this was usually the other way around, or that the mechanism that allowed their survival in the first place was “change something in the immune system, see if it works, repeat until it does”. Through some magical process of biology or chemistry afterwards, the found solution is then “remembered” and ready to be deployed again if the disease returns.
Oh, yeah, I know about that. I understood that it didn’t work on everything, though. (Well, it doesn’t work on the common cold, for a start, although I’m not sure if that kind of constant low-level mutation is feasible for more … powerful … diseases.
I’m not an expert, but I don’t think that a single individual, or even a small team, could do that.
The genetic variety created and maintained by sexual reproduction pretty much ensures that no single infection mechanism is effective on all individuals: key components such as the cell surface proteins and the immune system show a large phenotypic variability even among people of common ancestry living in a small geographic region (that’s also the reason why finding compatible organs for transplants is difficult).
Even for the most infectious pathogens, there is always a sizeable part of the population that is completely or partially immune.
In order to create an artificial pathogen capable of infecting and killing everybody, you have to engineer multiple redundant infection mechanisms tailored to every relevant phenotipic variation, including the rare ones. Even if your pathogen kills 99.99% of human population, far more than any natural pathogen ever did, there would be 700,000 people left, more than enough to repopulate the planet.
Is this actually true? Of course, few diseases would actually have good odds of infecting everyone, but surely that’s more a matter of exposure. [EDIT: or how you define “partial immunity”.]
By “partial immunity” I mean that you catch the disease, but only in attenuated form, maybe even subclinical or asymptomatic, and usually develop full immunity afterwards. This happened even with higly infectious diseases such as the medieval Black Death (Yersinia pestis), malaria, smallpox, and now happens with HIV.
AFAIK, a superbug capable of infecting and killing everyone doesn’t seem to be biologically plausible, at least without extensive genetic engineering.
Well, genetic engineering is a common part of scenarios like this.
However, it was my understanding that not all natural diseases grant immunity to survivors. I’m not an expert, of course.
Tetanus doesn’t grant immunity if you actually get it and survive. They are soil/intestinal bacteria normally and they don’t grow within you to a high enough number that your immune system can get a good look at them, their toxin is just potent enough that even at low concentrations it kills you.
There are also protist pathogens which express vast quantities of a particular coat protein on their surface such that when you form an adaptive immune response agains them it is almost certainly against that protein—and something like one in 10^9 cell divisions their DNA rearranges such that they start expressing a different coat protein and evade the last immune response that their host managed to raise, resetting back to no immunity.
Aha, I knew it!
That’s really interesting, actually.
I’ve been led to understand that this was usually the other way around, or that the mechanism that allowed their survival in the first place was “change something in the immune system, see if it works, repeat until it does”. Through some magical process of biology or chemistry afterwards, the found solution is then “remembered” and ready to be deployed again if the disease returns. I’m not quite sure whether anyone understands the exact mechanism behind this magic, but I certainly don’t (yet). *
By “the other way around”, I mean a selection effect; they survived because they were already more resistant and had the right biological configuration ready to become immune to it or somesuch. I’m not clear on the details, this is all second-hand (but from people who knew what they were talking about, or so it seemed at the time).
* ETA: Got curious. Looks like there’s a pretty good understanding of the matter in the field after all. +1 esteem for immunology and +0.2 for scientific medicine in general. And those are some really great wikipedia articles.
Oh, yeah, I know about that. I understood that it didn’t work on everything, though. (Well, it doesn’t work on the common cold, for a start, although I’m not sure if that kind of constant low-level mutation is feasible for more … powerful … diseases.
EDIT: turns out it is.