you might want to read a book by Christopher Mason from NASA called “The Next 500 Years: Engineering Life to Reach New Worlds” it’s particularly about the genetics and genetic engineering approach to life spreading from Earth to other planets and star systems. He covers the idea of not contaminating other planets or allowing us to be contaminated by them. It’s a recent book pushed around 2021. There’s also a Google Talks ad where he talks about the timeline of the book briefly, here’s a link Dr. Christopher Mason | The Next 500 Years | Talks at Google - YouTube and there are others on YouTube. I hope this helps.
Not having viruses present at all is not too likely.
Any animal species we bring will likely need their specific microbiomes too, including their own trillions of viruses.
As to the ones that cause illness commonly? As noted, like this thread some lie dormant for periods of time and reactivate. But what if the space-farers had been immunized for chickenpox and had disease? The vaccine was a live virus that also sticks around. It reactivates less commonly but still does.
What if we could come on board with none of the pathogenic viruses in any organism? How long would it take for new pathogenic ones to evolve and how much worse would our colonists be for having had no past exposure to similar viruses?
Obviously no one knows, but we’d by necessity be living in close proximity to our imported flora and fauna, each of which has their own sets of trillions of bacteria and virus as parts of their necessary systems, each mutating constantly. I’d bet much less than eons, likely less than generations, especially as the population grows. And each new one would of course be a novel blankivirus, hitting a population with no immunity to it or even anything similar to it. Probably not good.
I’m wondering if interstellar colonists could be protected against their own microbiota. Rather than remove all of these microbes and replace them with nothing, perhaps we could create new artificial microbe-like devices which lack the capability to evolve. This would allow the colonists to have intestinal flora that could never present a threat.
The problem doesn’t stop there; all the bacteria in the soil would need to be replaced by similar artificial organisms, and any animals (of any kind) we take with us would also need supportive, artificial, non-evolving internal microflora as well. One way to achieve this goal might be to only send completely sterile spacecraft to the destination system, and when it arrives it creates an entire ecology from stored DNA (and other data) it carries on board. Such a seedship might be much smaller and less massive than a generation arkship containing a breeding population of every species required at the destination. In interstellar travel, the mass of the payload is a paramount consideration.
One major drawback with such a strategy would be that the manufactured, artificial ecology that emerges as a result would be almost completely incapable of evolving. If the environment in the new system changes in any significant way, the organisms in that environment would be mostly unable to adapt.
There was a flurry of items in the news a while ago about fecal transplant (!) as a treatment for some conditions - basically inserting into a person’s lower intestine the assortment of gut bacteria from a healthy person, to help develop a healthy balance of necessary gut bacteria.
I suppose the problem is - how do you “clean” anyone or anything going out to the stars without killing them (or making their gut very unhealthy?)
I don’t think you can make a virus or bacteria incapable of evolution, since as I understand, evolution is just the result of transcription errors in DNA reproduction causing mutations. But presumably yes, you could by isolation and treatment ensure that the most dangerous pathogens have essentially vanished - as we have done with smallpox (we hope).
The problem is that bacteria and viruses, good bad or ugly, are a necessary part of the ecosystem we depend on.
Even if we could screen out all pathogens and establish a sterile colony, there will already be a host of microbes waiting for us and, inevitably, a percentage of them will be pathogens. That is going to be a very big problem because the colonists will have no resistance to them because they have never been exposed to them. They could conceivably be wiped out completely.
We may have to remain in orbit for an indefinite period of time while we collect and analyze as many of them as possible . We could try to develop medical counter measures to neutralize the most dangerous ones.
Always? I admire your optimism.
Another possibility is that most, nearly all, or all, other systems in the universe have no life, microbial or otherwise.
I would hazard a guess that it is a VERY small possibility because, it the planet has the necessary prerequisites for human colonization, it also has the necessary prerequisites for a plethora of different life forms. To me, at least, it is totally illogical to think otherwise.
You are probably right. But there are natural methods of reducing the mutation rate; it may be possible to improve upon these sufficiently well to make mutation a negligible problem.
To the extent that they will have a different biochemistry that may not agree with us (probably don’t want to breathe the air or drink the water or eat any native plants/animals either!), sure, any extraterrestrial bacteria is going to technically be a pathogen.
In terms of the original post and most of the subsequent discussion, it focused more on viruses. Those are less of a concern (perhaps no concern for several centuries), save any we bring with us.
I recall reading a review of a book about the smallpox epidemic in the Pacific northwest (BC and Alaska) in the late 1800’s. Entire villages were wiped out. However, contrary to the prevailing idea that the native American immune systems could not cope with a Eurasian disease, the author used statistics and historical records to point out a more insidious truth - the disease would attack one isolated village at a time when a traveler brought it in. Suddenly, everyone on the village is infected simultaneously. Nobody is immune. People died from lack of care in a subsistence setting while feverish - dehydration, starvation, exposure. Where there was someone immune to care for them - a missionary or a previously exposed villager - the survival rates were far better, sometimes only the same 10% mortality as with European outbreaks.
There are two issues - speed of transmission and severity of symptoms. People are not going to die en masse from the common cold or chicken pox. However, keep in mind the scourges we now vaccinate against would kill up to half the child population in crowded cities in the 1800’s - because child immune systems are still developing.
I tend to agree; but until we detect at least one example of life that originated elsewhere other than Earth, we cannot dismiss the possibility.
Three standard fair dice have all the necessary prerequisites for rolling three sixes. The three sixes could look and say boy 100% of the rolls I know of with these sorts of dice came up three sixes.
How often will those dice roll three sixes?
It is not logical to assume the necessary prerequisites are more likely to produce life or not until you’ve seen lots of rolls.
If the planet did not evolve life, then all sorts of other issues arise - the planet will be hazardous to human life, since the atmosphere will not contain oxygen. The question is with what do we seed the oceans to produce free oxygen, and how fast will that process go? Will it produce problem in the future, considering some algae blooms are toxic to other life; can we seed a variety of life? When can we stop wearing masks and oxygen feed? Is it a trap - Earth-capable planets will have a run-away greenhouse effect in the habitable zone, and the ones with temperate climates will freeze solid once we remove the CO2 greenhouse gas…? Will methane be a common atmospheric gas (also a greenhouse gas) since there is no oxygen to burn it?
Plant life will rely on the microbes in the soil to help produce the necessary nutrients, so we’re back to seeding assorted microbes. Some plants need insects. You would have to design an entire ecology, with the risk that evolutionary pressure may fill in the missing gaps.
Planetology can take you into many deep rabbit holes.
Curiously enough, I’d rather have a planet with no oxygen (and no life) than one which does carry a pre-existing biosphere. Any planet with an ecology could harbour pathogenic microbes, and even if it doesn’t, the biosphere is likely to be so different to our own from a biochemical viewpoint that it would not be possible for us to live there without removing, displacing or damaging the native lifeforms.
Better to find a lifeless planet and make carefully-controlled environments on the surface, or custom-build our own habitats in space, and avoid contaminating the local worlds.
Yes. My point would be that any earth-size planet that did not evolve life would include issues that present assorted known and unknown dangers. I pointed out the greenhouse issue with CO2 and methane. There’s also the problem of acids, if there’s sulphur in the atmosphere (Venus?). There’s the suggestion too that Mars presents a problem with very fine toxic dust and salts. (But likely most due to its dryness). Without free oxygen, there’s no protective ozone layer.
The question would be how fast you could convert such a world to livable, presumably by seeding it with appropriate plants? Are we talking decades or millennia? If it’s too long, then starting the project might be an interesting venture, but really what is there down on a planet, deep in a gravity well with a more lethal environment? Anything that can’t be mined from the smaller moons or planets and comets?
To get back to the OP question, you have largish settlements in self-enclosed environments, i.e. space cities. What precautions are necessary to prevent infections from incoming visitors? You can sterilize their waste products, but there’s not much you can do to sterilize a live organism. Isolation helps, but is not a guarantee. Will you have the equivalent of our “flu season” after the wrong ship docks?
To the OP’s question - Interesting data point in the news now, about the surge in respiratory virus cases in young children.
It appears to be a confluence of causes, but basically:
-it’s the start of a normal flu and cold season.
-Suddenly everyone is bringing home more air-borne diseases from work or school, or socializing
-parents and children have had minimal exposure to airborne diseases, thanks to masks and work/school from home. So they are encountering such diseases for the first time in 2 years.
-exposure is growing to critical mass to begin spreading more widely.
-children with less exposure to diseases for a year or two have had less opportunity to develop their immune system - seems most pronounced in younger children. Hence, more serious reactions to disease when they do get them.
As with everything to do with the human body, YMMV greatly. What makes one person deathly ill may not be more than a cough and stuffiness to another. But it seems the human body needs to exercise its immune system.
This seems to back up one theory that the boom in childhood allergies in recent decades is due in part to our hygiene, that the environment is too clean. Children’s immune systems which get no training against actual diseases may instead start attacking other foreign substances.
I do not disagree with your basic conclusion relevant to this thread, that the human immune system “needs to exercise”, but it is not clear that what is going on in young children is “more serious reactions to the disease when they do get them”. It is more a matter of many more infections with similar risk of serious disease per infection, hence an increase in absolute numbers.
Most of the kids getting hospitalization level ill are kids under one year with RSV. The last years could have been normal RSV numbers and they would not have past exposure for this year, as they weren’t alive then. And the vast majority of kids under one year with a first RSV infection, over 98%, do NOT get seriously ill. Most just get colds, some annoyingly miserable coughs, some mildly faster breathing than normal but are feeding fine and can be managed just fine with attentive parenting at home.
The issue is more what you labeled “critical mass” of exposures, that with a couple of years of virtually no exposures the pool of susceptible individuals, from preschoolers to adults, who overwhelmingly get no more than cold symptoms with RSV (especially past preschooler age) is way up. By now almost all understand the basics of how many more susceptible to infection causes greater spread, including to those at relatively higher risk of serious disease.
Several times more cases leads to several times more serious cases, even with the exact same risk of serious disease per individual.
Then there is a very unfortunate confluence - fewer pediatric hospital beds available than pre-pandemic. There had already been a long term trend of community hospitals getting away from having pediatric units. Other than brief periods of infectious disease peaks they usually have very little use. Pediatric inpatient care was never very profitable for hospitals. During the pandemic there were essentially NO pediatric infectious disease peaks; community hospitals closed those beds, converted them to adult beds, and the pediatric staff that didn’t quit minimally lost some skills as they moved to adult side. Those hospitals couldn’t open pediatric beds again on short notice even if they could get the corporate approval to do so.
So much more than usual peak demand for pediatric hospital beds and significantly less than usual supply of those beds … not a good situation.
And now influenza cases are picking up earlier than usual (with children under two at significantly greater risk of hospitalization on a per case basis also) … I am afraid.
Please, if you haven’t gotten a flu shot this season yet please do so ASAP.
Some detail on the problem of decreased pediatric hospital bed capacity from before this recent surge:
https://www.healthaffairs.org/do/10.1377/forefront.20220615.615247
So if understand, you are saying that there’s a wave of infections of older people (school and adult) who missed the opportunity to get these earlier, and are all at once about now bringing their not-so-serious RSV home to junior for his/her first time.
I.e. not more susceptible, just a lot more of them getting sick at the same time.
Just a lot more adults and children preschoolers and older who are getting infections (including many mild or even asymptomatic infections) at the same time because there are many more who are more susceptible to infection as a result of waning immunity. Thereby exposing many more babies to their first infections at the same time. Not more older children or adults more likely to have more severe illness from it.