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Comment by kaliqt | Hacker News Reader

Checkmate parasites.

But seriously, I worry about this level of parasite infecting humans one day.

Well the Guinea worm does force humans to get into water to complete the parasitic cycle. But it's also on track to be fully eradicated.

I think a parasite affecting human behavior in a substantial way is risking detection and elimination. So unlike with mantises this decreases the chance of survival, unless you paint a zombie-apocalypse kind of scenario.

A successful human parasite has to alter the host behavior in a very subtle way. This could be happening even now and we wouldn't know. There's some evidence this is the case with toxoplasma increasing affection towards cats.

>But it's also on track to be fully eradicated.

Thanks to Jimmy Carter! (And also a guy named Donald Hopkins, who's not me.)

https://www.cartercenter.org/about/experts/donald_hopkins.ht...

Humans routinely have very weird behaviours and while often we classify them as illness who knows how many of those we just call "a political view".

As you say, there are a lot of these connections, another is increased religiosity with neurological disorders like epilepsy and schizophrenia.

https://pmc.ncbi.nlm.nih.gov/articles/PMC4073495/ https://www.researchgate.net/publication/384855860_Religiosi...

SSRIs, birth pills and other 'harmless' drugs modify behaviour too.

Fwiw food and lack thereof modifies behaviour too.

If I fail to eat regularly for about 3 days I sink into a deep funk which takes a few days of regular eating to come out of.

I used to/have a problem where I just don't have the energy to eat due to being hungry and its a viscious cycle.

What happens when you fast?

Isn’t that failing to eat regularly?

No, because it's done intentionally.

This idea has grown on me a lot after watching Sam Harris’ 2013 Ted Talk, on deconstructing religion, logic and morality:

https://youtu.be/qn3ITqtGzQ8

Star Trek actually did an episode which addresses such a parasite. The episode was one of several episodes banned in a few places, I think for showing how the uninfected humans had to eradicate the infected humans violently.

Star Trek did a whole Wrath of Khan that addresses such a parasite :p

> Well the Guinea worm does force humans to get into water to complete the parasitic cycle.

How they do this [0]:

- Humans typically get infected when they unintentionally ingest copepods while drinking water.

- During digestion the copepods die, releasing the D. medinensis larvae. The larvae exit the digestive tract by penetrating the stomach and intestine

- About a year after the initial infection, the female migrates to the skin, forms an ulcer, and emerges.

- Upon reaching its destination, the worm forms a fluid-filled blister under the skin.[5] Over 1–3 days, the blister grows larger, begins to cause severe burning pain

- When the wound touches fresh water, the female spews a milky-white substance containing hundreds of thousands of larvae into the water.

- The larvae are eaten by copepods, and after two to three weeks of development, they are infectious to humans again.

[0] All of the above was copy & pasted from: https://en.wikipedia.org/wiki/Dracunculiasis

Part of the eradication effort was hacking this mechanism by convincing humans to use a closed container of water when this happens. The contaminated water can then be safely disposed thus breaking the cycle.

Or maybe it could alter the behaviour in a positve way: https://en.m.wikipedia.org/wiki/Parasites_Lost

https://en.wikipedia.org/wiki/Behavior-altering_parasite

The parasites you should be worried about are memes (in the biological meaning - an idea that forces host to reproduce and spread it - not "a funny image" meaning).

We already have such ideas that change human behaviour on massive scale and cause millions of deaths.

An STD that increased human promiscuity seems like it could be really successful at spreading. I wonder if any existing STDs have evolved to do anything close to this.

The social stigma around being seen as "dirty" for having an STI is known to drive the infected into more risky sexual behaviors and less hygienic partners. This is why normalizing testing and treatment as everyday things are part of the public health effort.

Doesn’t seem like it from the ones we know about, and I think that’s why we know about them. STI symptoms are typically unpleasant, painful, and when untreated potentially deadly. HSV for example is most contagious when a person is having an outbreak of sores, which certainly wouldn’t put most people in the mood.

They do and are what people in the past would call "demons".

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