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Humans Might Be So Sickly Because We Evolved to Avoid a Single Devastating Disease:
Sialic acids are a diverse group of carbohydrates that blossom like leaves from the tips of proteins covering the surfaces of human cells.
[...] Changes in sialic acid markers can give rise to a number of diseases. But it was one specific change particular to all humans that the researchers here were most keen to gain an understanding of.
Most mammals – including closely related apes – have a compound called N-glycolylneuraminic acid, or Neu5Gc. We've known for some time that the gene for this version of sialic acid is broken in us, leaving its precursor form, N-acetylneuraminic acid (Neu5Ac), to do its job.
Researchers previously speculated that this mutation was selected for in humans to make it harder for devastating malarial parasites such as Plasmodium knowlesi to latch onto red blood cells.
[...] Since chimpanzees retain the gene for Neu5Gc, the mutation must have occurred within the past 6 million years or so, sometime after we parted ways from one another.
[...] This most recent study shows Neanderthals and Denisovans share our variant of sialic acid, meaning the change happened before our branch of the family tree separated roughly 400,000 to 800,000 years ago.
[...] To differentiate between cells that belong to us from possible invaders, our immune cells are armed with a scanning chemical called sialic acid-binding immunoglobulin-type lectins. Or Siglecs for short.
When an inspection occurs, if a cell's sialic acid marker isn't up to scratch, it's curtains for that cell. Naturally, any changes to our sialic acid name-tag would imply our system of Siglecs would have needed adjusting as well.
Sure enough, on further investigation the researchers found significant mutations among a cluster of Siglec genes that are common to humans and their ilk, but not great apes.
[...] Siglec expression is linked with conditions such as asthma and Alzheimer's disease, raising the possibility that protection from a devastating disease put us at risk of other conditions.
Journal Reference:
Naazneen Khan, Marc de Manuel, Stephane Peyregne, et al. Multiple Genomic Events Altering Hominin SIGLEC Biology and Innate Immunity Predated the Common Ancestor of Humans and Archaic Hominins [open], Genome Biology and Evolution (DOI: 10.1093/gbe/evaa125)
(Score: 4, Insightful) by inertnet on Monday August 10 2020, @12:49PM (18 children)
I believe that's because while growing up, our immune systems don't get challenged as much as before. Contrary to what commercials are trying to sell us, a squeaky clean house may not be the best environment for your kids.
(Score: 1, Interesting) by Anonymous Coward on Monday August 10 2020, @01:15PM
There's also the extremely high rate of urban living and very bad air pollution in many cities. Was anybody measuring asthma during early industrialization when air pollution was supposed to be much worse?
(Score: 1, Interesting) by Anonymous Coward on Monday August 10 2020, @01:20PM
I think there are arguments to be made on both sides.
For example most bacteria that switch on their antibiotic resistance traits will often eventually revert back to their prior states if the antibiotic is removed from the environment. While the bacteria can make adaptations to fight the antibiotic the cost of those adaptations make them undesirable if the antibiotic is absent in the environment.
Likewise we have an immune system with various functions and adaptations. But those adaptations aren't free, they come at a cost.
An obvious example could be sickle cell anemia and malaria. Having sickle cells isn't necessarily a good thing. But if you are heterozygous the cost to you is minimal (though there is still a small cost to you directly there is a potentially much larger cost to your offspring) but the benefits to you of being resistant to malaria outweigh the cost if you live in an environment riddled with malaria. If malaria doesn't exist you and especially your offspring are much better off not having the sickle cell gene whatsoever.
(Score: -1, Flamebait) by Anonymous Coward on Monday August 10 2020, @02:16PM (1 child)
Yes, and if lockdown and other excessively sanitary measures continue for long enough what will happen?
The people hiding in their homes and behind masks are going to be screwed when forced to return to the real world as food and power shortages begin. The people out living, or even better "protesting", will survive. Imagine what happened to the Incas upon contact with Europeans.
(Score: 0) by Anonymous Coward on Monday August 10 2020, @02:27PM
Regarding "protests", bandanas as asks they all wear spread covid just as much or even more than no mask.
https://advances.sciencemag.org/content/early/2020/08/07/sciadv.abd3083 [sciencemag.org]
(Score: 4, Interesting) by meustrus on Monday August 10 2020, @03:10PM (3 children)
There was an interesting study I read last year that speaks to the effect of cleaning chemicals. It exposed baby animals to industrial solvents like sodium laureth sulfate which are often present in household cleaning products, even sometimes baby wipes, soaps, and lotions. Then it exposed them to common allergens like peanuts.
It found that the animals exposed to the solvents developed allergies to those allergens more frequently. Their theory is that these solvents break down the outermost protective barrier of the skin, and the infant immune system categorizes as dangerous whatever it sees getting past that missing barrier.
We need to realize that when there are billions of germs in our homes, killing 99.9% of them still leaves millions of germs. It's not possible to maintain a house with children like it's some kind of scientific clean room.
If you're going to be worried about disease, just follow the CDC's COVID guidelines - wipe down door handles and light switches with a mild detergent, and avoid sharing air with sick people. Clean wounds to avoid infection. Don't try in vain to sterilize your house. Plain water will clean most things; rubbing alcohol will disinfect and clean shiny surfaces without streaking; soap and detergent helps with greasy messes and germs, but not much else; peroxide dissolves organic substances like blood, feces, and dyes; vinegar+baking soda is cleaner and more powerful for difficult messes than any single home cleaning chemical you can buy. Never use bleach wipes. You're probably not using them right anyway - check the instructions.
If there isn't at least one reference or primary source, it's not +1 Informative. Maybe the underused +1 Interesting?
(Score: 0) by Anonymous Coward on Monday August 10 2020, @03:25PM
In the USofA, plain water will dissolve most things.
(Score: 0) by Anonymous Coward on Monday August 10 2020, @05:11PM (1 child)
The problem is people are trying to wash "dirt" away and the skin of kids is suffering. How many kids with patches of eczema all over their bodies? This didn't happen 100 years ago. Even 50 years ago. How many times did you see "dirty" kids walking around? And today? You are lucky to see them outside of their sterilized house.
Stop cleaning and start actually protecting kids. You know, lock away the chemicals and stop spraying your fucking laws with poison and let the kids get dirty. The 3 things consumerism + Dow Chemical (or J&J or P&G) ads certainly don't want you to do.
(Score: 0) by Anonymous Coward on Tuesday August 11 2020, @05:05AM
I have something dirty for them to play with - let me bring it outside...
(Score: 0) by Anonymous Coward on Monday August 10 2020, @03:55PM
Might be different if it was your kids that died, eh?
(Score: 2) by istartedi on Monday August 10 2020, @06:09PM (6 children)
This was apparently true for polio. I read something about how while it had always been a thing, it wasn't that common because toddlers played in the dirt. If you're a toddler it's apparently less likely to kill you. Then people moved in to situations where they played outside less, or in streets that didn't have soil with polio virus in it. As a result, they were exposed to the virus later in childhood when it had a worse outcome. The whole thing got really bad shortly after WW2 when that "clean house" lifestyle was being promoted; but I'm not sure if they ever documented a connection. Crowding in to cities probably didn't help either. Fortunately we got the vaccine so there was no need to learn more.
Appended to the end of comments you post. Max: 120 chars.
(Score: 2) by Reziac on Tuesday August 11 2020, @02:59AM (5 children)
Doesn't explain why polio persists in some of the dirtier countries; still endemic in Pakistan, Afghanistan, and Nigeria. Scroll down to the map:
https://ourworldindata.org/polio [ourworldindata.org]
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by istartedi on Tuesday August 11 2020, @07:19AM (4 children)
Most likely that has little to do with cleanliness, and more to do with getting vaccines distributed to remote war-torn areas where people distrust the health workers who are distributing the vaccines--sometimes for very good reasons due to past unethical testing.
Appended to the end of comments you post. Max: 120 chars.
(Score: 2) by Reziac on Tuesday August 11 2020, @01:08PM (3 children)
That might explain Afghanistan, but not Pakistan or Nigeria.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 3, Informative) by istartedi on Tuesday August 11 2020, @08:02PM (1 child)
Here's a good read on Nigeria. [plos.org]. If you skim the top it just looks like garden variety anti-vacc, but the historical context and documented abuses are down towards the bottom.
Pakistan has the disputed territory of Kashmir. It can't be easy to distribute vaccines there.
Appended to the end of comments you post. Max: 120 chars.
(Score: 2) by Reziac on Tuesday August 11 2020, @08:34PM
Ah, the relevant portion:
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“Since September 11, the Muslim world is beginning to be suspicious of any move from the Western world…Our people have become really concerned about polio vaccine” [14]. In the same article, Datti Ahmed, a Kano-based physician who heads a prominent Muslim group, the Supreme Council for Sharia in Nigeria (SCSN), is quoted as saying that polio vaccines were “corrupted and tainted by evildoers from America and their Western allies.” Ahmed went on to say: “We believe that modern-day Hitlers have deliberately adulterated the oral polio vaccines with anti-fertility drugs and…viruses which are known to cause HIV and AIDS”
===
I knew this was going on in Pakistan (not Kashmir, the whole country) but had not heard that it had taken hold in Nigeria.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 0) by Anonymous Coward on Tuesday August 11 2020, @08:11PM
Pakistan and Afghanistan share a border, and have similar problems.
(Score: 3, Interesting) by dwilson on Tuesday August 11 2020, @12:24AM (1 child)
Personally, I think it's a statistics thing. As in: everyone knows that statistically, smoking greatly increases your likelihood of getting lung cancer, but nearly everyone also knows a 60+ year old pack-a-day-since-they-were-thirteen smoker without a trace of lung cancer in them.
Me, I've got mild asthma that flares up now and then based on a few environmental triggers that I thankfully identified long ago, so it's manageable. I was also born and raised on a farm, playing in the mud and the dirt with dogs and cats and the occasional fox (domesticated). So that blows the kids-these-days-and-their-squeaky-clean-houses argument out of the water, at least as far as a slam-dunk cause-effect relationship goes. But there's still probably something to it, statistically.
- D
(Score: 0) by Anonymous Coward on Tuesday August 11 2020, @08:13PM
Did you play in the chicken coop without a mask? Particulate damage can do nasty things to the lungs.