Submitted by Dunkachin0 t3_103z74y in askscience
--_pancakes_-- t1_j32hk9z wrote
Reply to comment by masklinn in Where does all of the snot come from when you have a cold? by Dunkachin0
But what is the function for this excess production of this mucus?
Is this actually a useful mechanism against diseases like the common cold? Or is it just a trait carried over from the likes of the fish you mentioned in your comment, which actually utilised the mucus production as a defence mechanism?
masklinn t1_j32iffy wrote
We're getting outside of my meagre knowledge so hopefully a 'doc or other biology-inclined specialist will swing by. I know that in e.g. the lungs it's the only way to evacuate junk (e.g. dead viruses and immune cells), but for the nose I don't know if it's functional or if it's just a side-effect of the inflammation of the mucosa which is not deadly enough to get weeded out by natural selection.
Naive_Piglet_III t1_j32tqpo wrote
I remember talking to a medical student who explained that it also acts as a first line of defence. It has the ability to bind potential parasites in the nasal region where they potentially get killed by specific immune cells or are expelled via cough / sneeze.
Some virus (most common cold) have also evolved to survive this which is why you catch a cold if someone sneezes on you.
3chzpizza4brkfast t1_j35nd6q wrote
RN here. Mucous is secreted when your immune system detects a pathogen (virus or bacteria) and WBCs among other immune cells make up mucous therefore engulfing it and killing it or blowing it out your nose
Spider-Ian t1_j35sbdw wrote
Do you know anything about sinus infections? Like why is the mucus such a different texture? And why does it keep building back up after it's emptied for like a week?
[deleted] t1_j32inpp wrote
[removed]
--_pancakes_-- t1_j32kw85 wrote
Thanks for the explanation. I always wondered whether mucus production shooting up was a side effect of flu or a defence mechanism against it.
Peiple t1_j32mm6x wrote
Most of the symptoms you get when you’re sick aren’t due to the actual pathogen, they’re because of the body’s response to them. Fevers, cough, runny nose, lethargy, inflammation, sore throat, and decreased appetite are all ways your body works to keep you safe. Even though they’re not pleasant, it’s worse for the pathogen than it is for you. The severity of the symptoms is determine more by how much immune response you need. The influenza virus causes very very few (if any) of the symptoms you commonly associate with “the flu”.
There are cases where this doesn’t happen and you instead just see the actual pathogen’s effects—a good example of that is syphilis, which doesn’t trigger any immune response. Unlike flu/cold/etc you don’t get many symptoms at all (no fever/cough/runny nose/lethargy/etc), until you start experiencing bone decay and brain damage from the bacteria eating away at your internals. Pretty cool in a scary way.
Edit: and one cool addition to this is the story of how they initially treated syphilis—they discovered that if you inject a patient with malaria, the immune response triggers a high fever, which kills the syphilis. That could be followed up with antimalarials to “cure” the patient…although it had a pretty high fatality rate and was also developed through some questionable ethics. Luckily penicillin was discovered soon after, which was significantly safer. Moral of the story is that being sick helps you get better and not die.
mschuster91 t1_j32opaa wrote
And the problem is that there seem to be [https://sph.unc.edu/sph-news/antibiotic-resistant-form-of-syphilis-bacterium-identified-in-patients-in-cuba/](some strains of syphilis) on the rise that are resistant to antibiotics. It's only time until there's a truly multi-resistant strain, and infections are on the rise in general over all STIs - and as we've seen with covid, the more infections the more mutations.
Peiple t1_j32q3yp wrote
That’s true, although syphilis in general has a really tough time evolving resistance to antibiotics. It’s not necessarily true that we’ll inevitably get bacteria with resistance to all antibiotics—bacteria have a significant trade off to evolving resistance, since it usually decreases their overall fitness compared to wild type. That’s why you’ll typically see bacteria revert to sensitivity in the wild, and most multi drug resistant bacteria are only acquired from environments with lots of antibiotics (hospitals).
There’s also some drugs that are really difficult for bacteria to evolve dual resistance to—in S. aureus for example, it’s nearly impossible for them to simultaneously resist methicillin and vancomycin.
More infections = more mutations is also not necessarily true, especially since syphilis is a bacteria and covid a virus. A lot of bacteria have more proofreading materials to prevent mutations, and bacteria that like to form biofilms will have lower rates of mutation. Bacteria also have longer competition against themselves and the microbes around them as they grow coupled with a lower reproduction rate, which enforces more selective pressure than on viruses.
Viruses don’t have a lot of these problems because they reproduce and mutate significantly faster, and they’re not susceptible to antibiotics. Antiviral treatments are a lot harder to target because viruses rely on the host more than bacteria, so a lot of the “targets” are things our body also needs. That’s one of the reasons a lot of antivirals have more common side effects and than antibiotics.
emptybottleofdoom t1_j32n2xq wrote
Yeah, if the pathogens or irritants move around randomly, and 90% of the volume they end up in is mucus rather than body tissue, and they get flushed, that's good for us.
Viewing a single comment thread. View all comments