The Swine Flu panic has me thinking. Lots of scifi has featured the idea of a virus that sweeps the world and kills off (or otherwise affects) all or most of all humanity.
Has this ever happened with any non-human species that were not confined in a relatively small geographic space? (Or for that matter, even one that was so confined)
In general, how plausible is this on even a theoretical level? Leave aside Andromeda Strain-style bugs from outer space, but do consider the 12 Monkeys scenario: a man-made virus intentionally designed to cause extinction.
I can only think of one somewhat relevant response to question 1: Colony Collapse. Last I read, they don’t really know what’s causing it, but it seems to a a pandemic of sorts among bees.
In order to get the whole world the virus needs to be slow enough acting to allow transmission before people figure they need to take precautions yet lethal enough that there is no cure and is ultimately fatal to most people.
That said I think the possibility exists for a very serious pandemic on the order of the Spanish Flu of the early 1900’s which wiped out about 1/3 or so of the European population. That is far from wiping out the human race but pretty staggering nonetheless.
I think you would need to design a virus that was communicable while causing no ill-effect for quite some time (for instance, a year), but once it turned harmful it would kill in a relatively short period of time.
Even still, you’d miss a pretty decent number of people who lived in remote areas.
The main issue is that telecommunications act in real time, while transmission is at fastest jet speed.
Imagine a virus that spreads like a rhinovirus (cold) and is as virulent as AIDS. I certainly see no theoretical reason that this can’t happen. On the other hand, there do seem to be people with natural immunity, so you might see 99% of the human race (and civilization) would go, but the species would carry on.
The Black Plagueis thought to have killed 30%-60% of Europe’s population in four years, no doubt aided by poor sanitation, malnutrition and other factors.
The Zaire ebola virushas a 90% mortality rate, but it’s considered relatively difficult to spread by any way other than direct contact with an infected host.
Airborne viruses are much easier to spread, but tend to have a much lower mortality rate.
The other barrier is that virsues tend to mutate and the mutation may be significantly more or less lethal than the original virus. The 2007 Uganda Ebola epidemic had “only” a 25% mortality rate.
If I were intent on destroying humanity I’d focus my resources on developing a stronger version of salmonella, a bacteria, not a virus. It’s hardy, can survive outside the body for long periods and can be transmitted several ways. A little genetic tinkering should be able to keep it ahead of antibiotics.
Right, and even if you were setting out to design this superbug, you couldn’t know if you’d tested it on enough subjects to know about that hypothetical immunity. If one actually did want to wipe out humanity, one would be well-advised to independently develop a half-dozen different superbugs, and release them all at once.
The trouble is that viruses tend to evolve lower lethality as they spread. Viruses that take longer to kill their hosts are able to spread farther, since once the host is dead they can no longer infect others. So any mutations for lower lethality are strongly selected for.
Very lethal viruses don’t spread quickly. So when designing your Doomsday virus you’ve got a perhaps insoluble tradeoff between deadliness and infectiousness.
Mumps may cause infertility in males (if they contract it as an adult…children who get it are not affected like that…I have no idea why). Not a foregone conclusion though, just a possibility.
There may be others I am unaware of. That one just sprung to mind.
Tasmanian Devils have a pandemic disease that causes tumors that will kill all members of the species that come in contact with it. Devil facial tumour disease - Wikipedia
They are in serious danger of becoming extinct in the wild because of this parasitic disease. It is apparently not a virus.
I’ve always wondered what would have happened if the AIDS virus spread as easily as the cold. Given that you can have it for years without showing much in the way of symptoms, it could have spread to most of the world’s population before anybody knew anything about it, and killed almost everyone before effective treatments were developed. (By comparison, before the Spanish Flu of 1918-1919 burned out, it had infected half of the population of the entire world. Imagine if HIV spread to 50% of the world’s population within a year or two of surfacing. :eek:)
The same basic principle still exists, but since some bacteria are able to survive outside of a host for an extended length of time they are somewhat more able to linger after killing their host, potential to infect another host.