Just for curiosity, I am a diabetic and I was wondering if humans would suffer from the same ilness if they were on other planets? Does the climate on other planets help the immune system? Will there be some new health problems?

  • $\begingroup$ Welcome to WorldBuilding.SE! Just to clarify, are you asking specifically about whether humans would suffer the same diseases on other planets? $\endgroup$ – F1Krazy Aug 2 '18 at 12:23
  • $\begingroup$ climate could have an influence, but I would rather seek diferences in biodiversity for such disease: new kind of food will maybe change earth diseases (and probably create new disease) $\endgroup$ – Kepotx Aug 2 '18 at 12:29
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    $\begingroup$ In the case of diabetes specifically yes a Human being has the potential to get diabetes regardless of what planet they are on $\endgroup$ – Ummdustry Aug 2 '18 at 12:42
  • $\begingroup$ do you think that the human body can be better,i mean the pancreas will have a very small chance of now working ? $\endgroup$ – Saffist3r Aug 2 '18 at 12:44
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    $\begingroup$ Welcome to Worldbuilding, Saffist3r! If you have a moment, please take the tour and visit the help center to learn more about the site. You may also find Worldbuilding Meta and The Sandbox (both of which require 5 rep to post on) useful. Here is a meta post on the culture and style of Worldbuilding.SE, just to help you understand our scope and methods, and how we do things here. Have fun! $\endgroup$ – Gryphon Aug 2 '18 at 13:20

Human diseases come from many causes.

Intrinsic: Some diseases are due to failures of the human body: mutations (probably most cancers), many auto-immune diseases (including diabetes, alas!), and diseases stemming from old injuries. There's no reason to think they'll be any different off-Earth.

Environmental: Cancers caused by radiation, poisoning due to effects of the environment, sunburn, etc. will go up or down depending on the local environment. It's easy to imagine habitable planets where nonetheless some of these diseases are more common. (UV and radiation in general are expected to be more of an issue on Mars, for instance.) Differences in gravity have already been shown to cause developmental changes that can alter health.

Bacterial and viral: What happens here depends on what we take along with us. We have wiped out smallpox and are close to wiping out some other diseases. It's reasonable to expect that quite a few pathogens can be prevented from emigrating to new planets along with people.

Zoonotic: Some diseases -- possibly most diseases if you go back far enough -- originally jumped to humans from animals where they are endemic in the wild population. (Ebola, for instance, almost certainly comes from an animal reservoir. HIV jumped to humans fifty or seventy-five years ago. Influenza may have come to us from birds.) It seems highly unlikely that we'll bring wild populations with us without eliminating any diseases that they carry. (Eventually, new diseases will evolved of course, but not quickly.)

Alien: It seems very unlikely that alien diseases will affect us -- our biologies will be too different -- but we can confidently expect that if their biology is at all like ours we'll be allergic to a great many of their proteins.

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    $\begingroup$ I added 1 sentence to the environment section. I thought about a whole separate answer, but yours is pretty solid, I figured it was better to just include gravity in the list. $\endgroup$ – SRM Aug 2 '18 at 12:52
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    $\begingroup$ “Sorry I cant come out to play: I have alien allergies.” $\endgroup$ – Joe Bloggs Aug 2 '18 at 13:02
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    $\begingroup$ If alien microbes like to eat us for our raw materials and energy reserves, though, we might be in big trouble. Although there's a good chance they'll latch on to better hosts. $\endgroup$ – corsiKa Aug 2 '18 at 16:00
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    $\begingroup$ Recent research suggests that cancers are caused by viruses that lie dormant after an initial infection, and not by mutations. This explains the communicable facial cancer that is currently wiping out most, if not all, of the wild Tasmania Devil population. This is also why there are inoculations for certain cancers, i.e. attacking the pathogen, not the disease itself. See also lower rate of subsequent cancers than predicted for Hiroshima survivors. $\endgroup$ – CJ Dennis Aug 3 '18 at 1:29
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    $\begingroup$ It seems likely that some cancers are caused by viruses, but we know for certain that many aren't. Cancer is a complicated group of diseases. $\endgroup$ – Mark Olson Aug 3 '18 at 1:47

It's more likely there would be new challenges for the immune system, related to the completely new aggression for which it has no experience at all.

Just imagine what happened to people in America and Australia when first met illness brought by western invaders.

Climate will also influence how the organism will react: i.e. if one is weakened by prolonged exposure to cold, it's easier to get lung related sickness.

This for illness induced by an external agent. For those related to body ageing or malfunctioning (think auto-immune diseases or simply growing old) I think it is more likely that a new planet and its climate will at best do nothing, at worst it will kill us faster.

My reasoning for this is that our body has been optimized for what we have on Earth (gravity, pressure, light, temperature, oxygen, etc.) Any change to this will have effects on the short and on the long term. On the short term we know something from some studies (like oxygen toxicity or gravity deprivation), on the long term we can only speculate.

  • $\begingroup$ You are right,but i'm thiking,if people get used to the climate and develop a better immune system does deseases that we know on earth will still exist ? $\endgroup$ – Saffist3r Aug 2 '18 at 12:41
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    $\begingroup$ @Saffist3r I'm puzzled as to why you'd think we'd develop a better immune system just because we were on a different planet. $\endgroup$ – RonJohn Aug 2 '18 at 12:49
  • $\begingroup$ @Saffist3r, see my edit $\endgroup$ – L.Dutch Aug 2 '18 at 12:52
  • $\begingroup$ As i know,the more we live in a harder conditions the more the body learns to adapt it self,that's why i said we'd develop a better immune system. @RonJohn $\endgroup$ – Saffist3r Aug 2 '18 at 13:06
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    $\begingroup$ @L.Dutch: I think you're right in emphasizing the immune system, but not for the reason stated. When the New World was opened, diseases migrated both west and east, but they were all human diseases which had evolved in people. Had the New World been unpopulated few if any diseases would have been traded. The real risk is immune system reactions to alien proteins which is likely to be significant even if they use a different set of amino acids. $\endgroup$ – Mark Olson Aug 2 '18 at 16:43

An important distinction is internal diseases vs external diseases.

Internal and external are not scientific terms for diseases, so lets clarify. By using these terms, I am alluding to Genetic vs Infectious Disease. But lets define our own terms.

Internal are those diseases that come from our own biology; diseases a person is predisposed to in their genes, or that come about as part of normal human life (examples, autoimmune, diabetes). External, are diseases caused by bacteria or viruses, (example pneumonia, HIV).

The same internal diseases like cancer, Parkinson's, etc will happen on other planets, and possibly at the same rates, but new internal diseases will be rare or non existent. This is because they are not related to the microbes around us but instead to our own bodies. If we are the same humans, then the frequencies of these diseases may change, but the types of diseases encountered probably wont. The obvious example of one that might change is more cancer with more radiation.

Externally caused diseases can be either bacterial or viral.

Diseases from bacteria are the most likely to differ from those on Earth. How they will differ will be determined by what kind of bacteria can grow in the new environments, and how their evolution may change because of this. For example if there is more material to decay on a new planet, then we may see speciation of bacteria that cause decay. This might lead to many more kinds of infections, and decay related diseases.

Viruses on the other hand probably won't change much. They are closely related to our own biology. So an alien planet likely wont have anything new that can affect us. There will only be what we brought with us, and any new strains that develop from them. How different these strains are from earth will be determined by changes in the way we deal with them on the different planets. If our doctors treat them in the same way on every planet, then they will stay the same.

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    $\begingroup$ I think you might be surprised by many internal diseases. Many cancers are appearing to have previously unknown viral factors (need to dig out the New Scientist article I got that from). It would be very interesting to see which cancers reduce significantly in prevalence and which remain steady. $\endgroup$ – Ynneadwraith Aug 2 '18 at 13:53
  • $\begingroup$ @Ynneadwraith here's the most recent report on the fraction of worldwide new cancer diagnoses attributable to infection. It's about 15%, and is relatively conservative. A large proportion of cancers are attributable to environmental exposures as well. There are very few entirely intrinsic diseases, possibly none. Even genetic defects with 100% penetrance (e.g., chromosomal anomalies like Down, Patau, and Edward syndrome) are associated with maternal risk factors. $\endgroup$ – De Novo Aug 2 '18 at 20:39

Mark's answer is great because it classifies the many causes of diseases. Let me make a note on a group of diseases I'll call "parasitic diseases", extending Mark's classification of bacterial and viral to include all kinds of live parasites, because almost all biological kingdoms causes diseases (except maybe archae and plantae, but I wouldn't bet on it). There are diseases caused by fungus (i.e. candidiasis), by protozoan (i.e. brain-eating amoeba) and even by animals (i.e. cysticercosis).

Diseases caused by living beings vary greatly geographically (there was no flu in South America before the first contact with Europeans) mostly due to evolution. In isolated environments capable of supporting life, like spaceships and potential off world colonies, new diseases will certainly evolve, both as variations of preexisting diseases and, eventually, completely new diseases may evolve from previously unharmful microorganisms.


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