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maggi90w1
01-28-2013, 05:53 PM
Ok, another question regarding my post-apocalyptic scenario.
This time for immunologists.

I have a population of a few hundred people living in an underground bunker. Of course, when they entered the bunker some of them where sick. Nothing dangerous, just the common flu.
50 years later the doors open and the people from the bunker come in contact with the survivors from above. I think it's save to assume, that the bunker people would be somewhat more vulnerable to all kinds of bacteria from above, especially the one born in the bunker but what about the other way around?
Could the flu virus they brought with them mutated enough to become dangerous for the survivors who spend all their life in the wilderness?

Bufty
01-28-2013, 06:21 PM
Sorry I can't help on your disease question.

But I can't help commenting that 50 years in a closed underground bunker is one hell of a long time for two-hundred people to be self-sufficient, and if there are survivors outside the bunker I hope you cover how they missed each other for fifty years.

And only one birth in fifty years?

Buffysquirrel
01-28-2013, 06:42 PM
Possibly there's an s missing from 'one'.

Wrt to the people in the bunker, the flu virus might not even survive in such a small population. Colds and flu reach Antarctic research stations from outside, frex, but quickly go around everyone and then there's nobody left to infect. Bacteria would probably pose the higher risk.

But in short, yes, both populations would be vulnerable to infections carried by the other. In a small gene pool, the alleles would also be limited, increasing vulnerability.

King Neptune
01-28-2013, 06:55 PM
The isolated population would have a greater problem with decreased immunity. Even if they were in the shelter for a year or two, rather than the absurd fifty years, everyone would have had all of the diseases that were available in all of their variations, and the disease bacteria and viruses would have largely died off from a lack of available food sources. There would be no flu viruses (as one example) circulating among them. Those same people would not have been acquiring immunity to diseases that were developing outside the shelter, and they would be infected quickly after leaving.

maggi90w1
01-28-2013, 07:22 PM
Hm, yeah... I see. It's not really working.

Btw, yes: there was an s missing from one.
And: The bunker was build a couple of decades from now to provide shelter during a nuclear war. It was designed to support a maximum of 600 people for 50 years (until the radiation level are low enough) and is at least partly self-sufficient. The door was closed with a timer and could not be opened from the inside or the outside without a security code that got lost early on. (everyone who knew the code died during the catastrophe or a couple of days later).

King Neptune
01-29-2013, 12:17 AM
Hm, yeah... I see. It's not really working.

Btw, yes: there was an s missing from one.
And: The bunker was build a couple of decades from now to provide shelter during a nuclear war. It was designed to support a maximum of 600 people for 50 years (until the radiation level are low enough) and is at least partly self-sufficient. The door was closed with a timer and could not be opened from the inside or the outside without a security code that got lost early on. (everyone who knew the code died during the catastrophe or a couple of days later).

If it really was for 50 years, then there probably would be no more than a dozen people left; the rest would have died in the feuds.

If the radiation were so high and long lived that it needed 50 to fall to the safe level, then it would kill nearly all vegetation, and any humans outside certainly would die.

In the 1950's and 1960's bomb shelters were designed to support people safely for a few months, and they were self contained; there was only one way in or out. Everything that the dwellers would need was there, and that included food. Your 50 year shelter would have to be huge to hold enough food for 500 people for 50 years. Just assuming that each person would need one pound of food every day means that they would have to pack 9,125,000 pounds of food. Let's assume that would be one liter in volume per pound. If all that food were packed into one room that was 8 feet high, then the room would have to be more than 200 feet square, or it would be a little less than 8 acre-feet.

Plains Pen
01-29-2013, 12:50 AM
I think that mutation of viruses to something deadly is an extremely rare event as evidenced by the fact that we haven't had many deadly virus mutations in the past 100 years -- think HIV. On the other hand, if you went 50 years in a hole without exposure to new infections, you would be at risk when you went into the real world. I can't see how everyone else -- since they had the same viruses around -- would be at increased risk from the flu that went down in the hole with you.

Sarita
01-29-2013, 12:59 AM
Just assuming that each person would need one pound of food every day means that they would have to pack 9,125,000 pounds of food. Let's assume that would be one liter in volume per pound. If all that food were packed into one room that was 8 feet high, then the room would have to be more than 200 feet square, or it would be a little less than 8 acre-feet.
And the 9M # is assuming 0 procreation.

Also, your offspring's disease immunity is reliant on a diverse suite of MHC genes in the parents. If you only had a pool of say 250 mates, you wouldn't be able to choose your optimal mate based on MHC incompatibility, thus lowering each generation's immunity to standard pathogens that affected the original population. This new group would be much more susceptible to the germs OUTSIDE the bunker than those outside being susceptible to the germs INSIDE the bunker (if they could have survived the radiation. I'm not a chemist or an MD, just an Anthropologist.)

Buffysquirrel
01-29-2013, 01:30 AM
Someone would have written the code next to the door. It's what people do.

maggi90w1
01-29-2013, 02:18 AM
Someone would have written the code next to the door. It's what people do.
Not if these someones are either dead or don't want people to leave.


If the radiation were so high and long lived that it needed 50 to fall to the safe level, then it would kill nearly all vegetation, and any humans outside certainly would die.
They have seed- and sperm banks, but that's not important because there was no nuclear war. The disaster was natural, but they used the bunker anyways.


Your 50 year shelter would have to be huge to hold enough food for 500 people for 50 years. Just assuming that each person would need one pound of food every day means that they would have to pack 9,125,000 pounds of food. Let's assume that would be one liter in volume per pound. If all that food were packed into one room that was 8 feet high, then the room would have to be more than 200 feet square, or it would be a little less than 8 acre-feet.
Well the catastrophe takes place a couple of decades in the future, so the bunker is equipped with underground farms and a food plant that recycles organic waste into food.

Unimportant
01-29-2013, 03:01 AM
I have a population of a few hundred people living in an underground bunker. Of course, when they entered the bunker some of them where sick. Nothing dangerous, just the common flu.
50 years later the doors open and the people from the bunker come in contact with the survivors from above. I think it's save to assume, that the bunker people would be somewhat more vulnerable to all kinds of bacteria from above, especially the one born in the bunker but what about the other way around?
Could the flu virus they brought with them mutated enough to become dangerous for the survivors who spend all their life in the wilderness?

If the bunker people (BP) entered the bunker with the flu, then presumably the same common flu/cold/whatever viruses were also within the wider outside population (OP). So, in both cases, the viruses have had 50 years to undergo random mutations.

Since the BP population = 250, and the OP population = ?millions, it's likely that the viruses will have mutated, reproduced, and survived in a larger number of variants within the OP compared to the BP. E.g., when BP and OP meet, BP will be more likely to get a 'new' virus from OP than v.v.

Either way, for a virus to have mutated into form that is dangerous/deadly for the other population means that its original host population must have likewise been selected for some trait that protects them from the virus (otherwise it'd be deadly for both groups). Natural selection in humans takes many generations, though in a small, closed breeding group like the BP, it could happen. What you'd need, theoretically, is to have a combination of circumstances:

1. Virus within BP mutates into something deadly.
2. BP is largely wiped out by virus, barring one genetically 'different' person who is protected agains the virus, and his/her relatives and offspring who carry that genetic difference.
3. Survival within the bunker then depends on carrying that genetic difference, necessitating inbreeding within the BP over the 50 year period.

Alternatively, the BP would have had to come up with some way to prevent/treat viral infection (maybe they invented a new anti viral or something out of sheer boredom while they sat around for fifty years); if they choose not to share it with the OP, the OP could be at risk.

King Neptune
01-29-2013, 04:39 AM
There are several large underground bomb shelters around the world that were designed and built during the Cold War. I have never been in any, but I have seen drwaings of the Cheyenne Mountain bunker (and it is huge), but none of those [pplaces are capable of supporting a population of several hundred people for more than a year, at the far outside. In addition to the problem with storing that much food, a closed ecosystem would break-down after not very log. Remember that closed ecosystems in Arizona (I Think it was called Biosphere)? It was designed to be able to operate without additional inputs, but it didn't work. I would assume that your place would be built on the lessons learned, but trying to make it last fifty years strains my credulity to the breaking point. I also have trouble with the "generaltion ships" described in some SF novels.