Have an Autoimmune Disease? Blame the Black Death

The bubonic plague killed so many people in Europe, the Middle East, and North Africa that that natural selection event is still rippling through our genomes today. But the same genes that helped your ancestors survive the Black Death may be contributing to autoimmune disease today.

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[deovolente]

Wow. I thought my body was too weak and trying to kill me. Apparently, my body is too strong and trying to kill me.

[mcmosfet]

There's an interesting book about this subject called "Survival of the Sickest" by Sharon Moalem that states the reasoning for this kind of genetic expression like this:
Q: "Why would you take a cure that kills you in 30 years?"
A: "Because it keeps you alive today."

Its an interesting reminder that evolution tends to ignore negative traits, as long as they don't prevent reproduction.

[jenniferburns]

As someone with Rheumatoid Arthritis, and many family members with autoimmune diseases, I knew something genetic was going on. I guess an adaptation that ensured survival during a pandemic ended up giving me a disease that is treated with immunosuppressants that put me at higher risk in the latest pandemic.

[petersmythe]

This is an excellent example of how natural selection can select for things, even in just one generation, that wouldn't necessarily be advantageous in every situation, only the current situation.

[astralb.]

My existing genetic condition was actually "awakened" by getting Covid in January 2020. It's very strange how, despite having had the mutation my whole life, a simple infection was what made me symptomatic

[SpawnofHastur]

There's a similar issue with Sickle-Cell Anemia - it turns out that when attrition due to malaria is very high, having sickle-cell anemia (or just being a carrier for it) improves your lifespan and thus your ability to spread your genes.

[germann]

It actually makes me somewhat happier about having crohns knowing that it’s from a history of my ancestors surviving!

[Jrockblam]

My battlebuddy for 8 years and one of my best friends has Crohn's. He hid it, and got it treated on the side for years because the Army would have booted him for it. Several deployments and he toughed it out and self medicated. It wasn't until he took some shrapnel and he had to stay at a hospital before they found out. One of the toughest and best humans I have ever met. You are a hero Gabe.

[SakiKei]

As a dane with 5+ chronoic disorders, one of them IBM, blaming my forfathers fits me quite well.

[aliaskaradylov]

I am from Kyrgyzstan and all my family has skin-related chronic autoimmune diseases. I, my father and my daughter have psoriasis, and my uncles and brothers have vitiligo. Taken that the Black Death was originated in Central Asia and to this day we still occasionally have cases of bubonic plague, I now understand why we might have adapted these annoying diseases.

[YuBeace]

Many of us have our auto-immune diseases "awakened" so to speak after an infection of some kind. But something I also noticed is that the side of my family that deals with the most auto-immune diseases also got through covid rather solidly. I guess it's easy to shoot down a pathogen when your guns are already out. I've always kind of suspected this may be a thing, so it's neat to hear a SciShow about this theory.

[spindash]

I’d been wondering for awhile if autoimmune diseases might be related to looking for an early, aggressive response to certain diseases. Should be interesting to see how this research pans out

[nola]

Resistance to hiv has also been linked to plague as well. What I've come to expect now is if your ancestors survived the plague, then you will be affected in other crazy ways.
My family was in the hardest hit parts of france and we have many people in my family have auto immune conditions.

[rolandtowen]

This kind of stuff is so fascinating! Reminds me of the "advantage" of being a sickle cell carrier in areas with malaria

[CosmicShieldMaiden]

My son has crohns, it’s horrific. He’s starting IV infusions next week😢

[angelasieg]

This was fascinating. I know one case does not prove a hypothesis, but here is my story. My husband was often sick as a kid. Always with gi illness. The doctor to his mom it was everything from viruses to he was faking it. When he was 15 he turned yellow and collapsed. Long story short he had undiagnosed IBD. Going untreated for so long it killed his liver. He had a liver transplant then a 2nd one 2 weeks later when the 1st one failed. We have been married for 22 years. In that time he has had two more transplant surgeries. Here is the funny thing, he almost never gets colds or the flu. We both got Covid a month ago and he had the sniffles. He had 1 day he felt sick enough to stay in bed. It happens every time. Someone gets a cold he feels a little off for a few day but recovers quickly. Even after all the transplants, surgeries, bouts of rejection and sepsis and lymphoma he is alive and working full time. He amazes us all including the doctors at UW-Madison Hospital.

[Nukeaon]

I've been diagnosed with Crohn's Disease now 20 years, it was exciting to see you guys did a video on this, thank you so much @SciShow team!

[capnstewy]

I get sick way less than my wife but I have an almost constant rash over large sections of my body. Thank you psirocis.

[nikknacs]

my dad died at 49 due to complications with lupus, at diagnosis there was literally nothing known about lupus, great to be learning about some of the causes

[poppletronva]

I remember listening to SciShow Tangents and hearing that Hank also had Ulcerative Colitis and it was really cool to see how much he gets done despite that.

I was diagnosed my senior year of highschool in 2017 and it closed a lot of doors at the time, but I pushed forward and found my own opportunity to strive towards something special. I had access to a mic and editing software, and started auditioning for small voice acting projects before slowly working my way. There have been a lot of ups and downs, but even when things were the hardest I could act... And well, this past month I've finally reached some of those really big lifelong goals and I have felt a lot of that hard work beginning to pay off.

There's still a long way to go, but I know for a fact that people with UC can do incredible things if they set their minds to it, Thank You Hank.