Comment by tomasreimers | Hacker News Reader

Comment by tomasreimers | Hacker News Reader

The mind-controlling--probably a better phrase for them is "behavior altering"--class of parasites are fascinating from an academic sense... and nightmare fuel from a day-to-day sense. Two additional cases which I remember studying in school are:

(1) A parasitic worm which causes snails to climb to clearly visible positions so that birds can eat them. These snails are usually avoidant of those positions, and so this is clear behavior alteration. (https://www.youtube.com/watch?v=fkiL-v4X8w8)

(2) A parasitic fungus which takes over ants, causing them to climb up high and then bite (!!! this means it can affect specific muscle movements) into a plant, before bursting from the body and spreading spores (https://www.youtube.com/watch?v=vijGdWn5-h8, apologies for the mildly dramatic nat-geo video)

And for a good piece of sci-fi on the first-person experience of seeing others rapidly/inexplicably change behavior, check out [The Screwfly Solution](https://en.wikipedia.org/wiki/The_Screwfly_Solution). (It's a good read intended as commentary on patriarchy, and it also uses a behavior altering piece of biology as a key plot device.)

There is a part of me that wonders if there are things (viruses/bacteria/funguses) which effect human behavior. And if in 100/1000s of years into the future we'll look back and realize that some subset of maladaptive personality traits and/or mood disorders aren't something that simply "happen" to someone, but are instead explained by biology/chemistry we didn't have a good understanding of. The same way we now look at ancient Rome and say "yeah, their use of lead pipes definitely had some effect on their psychology".

Then again, there is something deeply human to say "nah, we are fully in control of our psychology. These things only happen in simpler animals, and our more-complicated biology means this could NEVER happen to us".

It's not a theoretical concern. Take toxoplasmosis, which affects nearly half the human population and has measurable effects on human behavior.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2526142/

I've been curious for awhile and have failed to find references to how quickly the body clears toxoplasma gondii; I have read on and off about the vaccine work there, and it seems that once you've been infected re-infection does not occur.

It's surprisingly hard to find papers on clearance, but also hard to find papers on long term effects vs. effects while actively infected.

Toxoplasmosis is a chronic infection that is never fully cleared from the body. There is some evidence that the length of the infection correlates with strength of symptoms.

Ah. That does explain it.

I was thinking about toxoplasmosis as well. Another example is syphilis (std), it is reported to lead in a certain phase to extremely good mood, which helps transmission.

Toxoplasmosis being commonly carried by cats is one of the main reasons I will never own one. I am certain it's not a coincidence that cat scratches are associated with depression.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4700762/

Interesting. I am not so certain. Scratching tends to happen when you play fight with a cat. I would expect people who could be described as depressed would care less about being scratched by a cat than those that aren't and are therefore more likely to be scratched.

Also the conclusion of the study you linked is that toxoplasmosis isn't linked to depression but scratching is. I found this unexpected given the wording of your post.

Edit: also when you clip a cat's claws it can't really scratch you. I'd also assume someone who can be described as depressed is less likely to clip or get their cats claws clipped often enough to prevent scratches.

Fairly sure that even thinking of clipping a cat’s claws is the dictionary definition of “scratched all to f#ck”.

I’d also suggest that the toxo-inflicted depression will be offset by the many added joys of being personally owned by a furry, purry, and only occasionally—ow, sharp!—bundle of utterly adorable fluff. Which is to say, humans are a bit more complex than ants, thus effects will be a lot less clear-cut.

Thanks for the chuckle. I agree with your suggestion.

It is much easier to clip my cat's claws than my Chihuahua's. I think it depends on the cat.

Note that the article supports your point:

the number of cats at home had a negative effect on depression (p = 0.021).

Suggesting that getting a cat is a good idea for someone concerned about depression. Of course, it may be that depressed people are less willing to take on the responsibility of pet ownership.

Interesting, but the phrasing means that the more cats you have the less subject to depression you are ?

I think you will start to see diminishing returns after 2 cats.

Yes, that is why it is "[s]uggesting getting a cat is a good idea for someone concerned about depression"

It's also extremely overblown. Even if a cat has toxoplasmosis, it's not contagious unless the cat is very sick itself and even then only through its' feces, which I suppose could get on a cat's claws, but for your normal healthy indoor/outdoor cat it's a non-issue.

Cat poops, cat buries poop with hind feet, cat gets picked up, cat hears a scary noise and digs back claws into your chest shoulders and head as it climbs over you to escape

indeed they do, and many many times over the years, if growing up with one

And they're fluffy and cute and a nice friend :-)

I mean, there is a sincere possibility that you only like cats because you're infected by a mind control parasite.

For real! Isn't that terrifying?

Only if you are clinging to the illusion of self :)

>cat buries poop with hind feet

That would be a dog.

[1] https://www.litter-robot.com/ exists and works for (some of) them.

Also, as many can-openers will know, some others will watch you doing your thing, without you being able to stop them, and learn from that to use the loo in comical but clean ways.

Comical as in how they crouch on the lid, hind legs spread wide, butt hanging low over the middle, forelegs on the front. Clean as in not hitting the lid. They basically want their shit "gone" without having to mess with it. If they see/watch/understand/learn a possibility to do that, they'll use it. (In my personal experience with the small sample size I have. Though there are many writings from others, describing the same)

I'm not sure, I never really thought about it much until my grandma. Her whole life she vehemently hated cats, literally believed they stole souls of babies. Black cats were just unthinkable to her. She'd never lived in a house with cats pretty much her entire life.

She ended up moving in with my aunt when she couldn't look after herself any more. My aunt had a small black cat. At first my grandma hated it. She was terrified of it, would shoo it away, kick him outside and stuff. But after a few months of living there, out of nowhere like a switch had been flipped, she suddenly loved that cat. She'd spend hours watching TV with him on her lap, would go looking for him to give him treats, would get concerned if he was outside too long, that cat became one of her favourite things.

I mean maybe she just had a change of heart after a lifetime of ingrained hatred and fear, but her attitude towards pretty much everything else never really changed.

When you get to a certain age, the constant worries of toxoplasmosis that one has while young fade away; especially if you have had children already. Companionship becomes more important. That's what has happened in my family, although I haven't warmed up to the idea yet.

It's also extremely overblown. Even if a cat has toxoplasmosis, it's not contagious unless the cat is very sick itself and even then only through its' feces, which I suppose could get on a cat's claws, but for your normal healthy indoor/outdoor cat it's a non-issue.

Or maybe that's just the T. Gondii talking.

Join us.. It's furry bliss

Depending on the personality of the cat(s) you're missing so much...

Personally I prefer dogs over cats. I've met cats that I liked but when I sat down and thought about why I liked those particular cats it was because they acted in ways I associate more with a typical dog rather than a typical cat.

It's a personal thing. On both sides. Can't argue with that. Just accept, or avoid/ignore.

Rereading it now, too late to edit with "On both sides" i meant for both involved parties. No matter who on the human side, no matter which animal. They may all have their common traits, but they are all on a spectrum of those :-)

(just to make myself clear...)

Correlation doesn't prove causation though.

From the article linked:

> Alternate explanations for the effects of T. gondii on humans cannot be ruled out. It is possible, eg, that individuals with certain personality characteristics behave in a manner that makes it more likely that they will become infected.

Here’s some anecdata for you!!

I hated cats until we got our first. At the time, I was in the midst of deep situational anxiety - a few days before we had just found out that a nuchal scan on my daughter detected a possible abnormality.

That was a situation I had absolutely no control over but I tend towards being obsessive. As my anxiety increases, I get more and more obsessive.

Bitey became the focus of that. Having a new little kitten gave me something to focus on aside from my fears.

Today, my daughter is four. Everything turned out great and she’s just the most wonderful little person I’ve ever met. But now I’m designing a cat tower with a fountain.

I don’t know if I have toxoplasmosis but if I did, that would sound like I’m a crazy cat middle aged dude. But, I was obsessive before and now I just love cats.

Or I’m in denial. It’s your choice!! :)

Well, I hate dogs and never owned one too.

A lot of people are talking about toxoplasmosis, but there's a more extreme example in the form of rabies, which basically makes you super aggressive and insane.

But only for a short time.

It's suspected that the entire stereotype of "lazy and stupid southerners" (in the US) was actually hookworm infections. This one not necessarily behavior altering, but just drastic malnutrition that eventually also affected brain function.

https://www.pbs.org/wgbh/nova/article/how-a-worm-gave-the-so...

I remember a RadioLab podcast episode related to this.

>It's suspected that the entire stereotype of "lazy and stupid southerners" (in the US) was actually hookworm infections.

It's an interesting suspicion and cool in a Freakanomics way, but it apparently lends little predictability.

From your article:

> But the South continues to lag behind the rest of the nation economically, with seven out of the 10 poorest states in the U.S. located there. And while stereotypes are fading, many outside of the region continue to look down on it. “When I told my family I was moving to Houston, it was like I was leaving for a leper community—they wanted to have a funeral for me,” Hotez says. “My in-laws certainly have perceptions about this being a backwards place, not realizing that some of the most sophisticated universities in the world are located in the South.”

They link to the bottom 10 states by poverty level. In fact the bottom 12 states for poverty level are in the South:

https://en.wikipedia.org/wiki/List_of_U.S._states_and_territ...

If hookworm was the cause and hookworm was solved, why are the states still so poor?

Or why don't they have University degrees?

https://en.wikipedia.org/wiki/List_of_U.S._states_and_territ...

> Or why don't they have University degrees?

I'm reminded of Massachusetts's Old Deluder Satan Act of 1647. Which required cities and towns to fund public schools.

https://www.mtsu.edu/first-amendment/article/1032/old-delude...

My offhand thought is for long standing cultural and historical reasons the leadership in southern states doesn't care about poor and working class education. Primarily you don't need to read to able to pick tobacco and cotton. Quite the reverse. Some places it was illegal to teach black people to read and write.

Where in the north the religious culture and industrial economy made it imperative that workers be able to read and write. Can't read, can't read the bible, surely will fall into the hands of Satan. And they'll use the wrong type of oil on a machine and wreck it.

Because other states already hogged all resources. Same reason why silicon valley isn't omnipresent.

> If hookworm was the cause and hookworm was solved, why are the states still so poor?

Imagine you have two runners who are running a marathon. The first runner has to carry a 50 lb backpack for the first 10 miles of the race. If you check their times for the midpoint of the race would you say carrying the backpack can't possibly be the reason the first runner is slower than the second? They aren't carrying it anymore (ie the problem is solved) so why didn't they catch up?

Or maybe the backpack was hot weather, religiosity, fervent individualism, and racism all along.

For a more recent sci-fi treatment, check out "The Girl With All The Gifts" by M. R. Carey, https://www.goodreads.com/book/show/17235026-the-girl-with-a.... A scary dystopian near-future tale of Ophiocordyceps unilateralis infecting humans.

Good book - recommended sci fi if you are into that sort of thing.

Pretty great movie as well. https://en.m.wikipedia.org/wiki/The_Girl_with_All_the_Gifts_...

Nah .. the book was great and the movie was only average.

Researchers have found correlations between certain infections and certain mental illnesses, and have speculated the infections may cause (at least partly) the mental illnesses. After reading the book Infectious Madness, I think causality is dubious. https://www.psychiatrictimes.com/view/infectious-agents-schi...

Edit: but then again I believe causality has been established between kidney infections and cognitive impairment

I take it you haven’t played “Last of Us”? It’s quite literally the entire premise of the game (what if Cordyceps infected humans?)

Funnily enough that game has probably taught more people about zombie fungi than biology textbooks.

I have not haha, although maybe I should :)

They're making an HBO show for it too by the creator of Chernobyl. It's a fantastic story and I'm glad more people will experience it.

The sequel just came out as well. Without saying too much, it was "controversial" to a lot of people seemingly aligned with bigotry but I thought it was amazing.

To others: If this were reddit, the mere mention of the game would spark outrage. I'm not sure if that will happen here but I see an alarming amount of hate speech here these days so I'll just say - I'm not accusing literally everyone who hated the game of being a bigot, but there sure were a lot of them.

Thanks for sharing. The HBO produced Chernobyl is one of a very few "really, really good" things I've ever watched. It kept my attention, my wife's, and my kid's. And we are very different people, with vastly different interests.

Absolutely. I loved that show. The Last of Us is obviously fictional but the stories have a very similarly melancholic tone so I have high hopes for it.

Edit: I wouldn't go googling it btw. Even if there aren't spoilers in the results YouTube, etc. will think you've played it and the aforementioned controversy has created a lot of trolls determined to spoil the ending in comments and article/video titles.

It was also controversial for a lot of reasons that had nothing to do bigotry, such as the way the main character from the previous game was handled, the depressing character arc of the main character of this game, a POV switch that many players found alienating, and an abrupt ending.

Now I don't agree with any of these criticisms, since I thought the game was amazing---but one has to recognize that there were defensible reasons to dislike the game.

I tried to address this in my last sentence but didn't want to get too specific because of spoilers. To clarify, I agree. Art is subjective and people who didn't like this game for non-bigoted reasons are absolutely allowed to have that opinion.

I just don't think I've ever seen precisely this level of toxic outrage over a video game before. A loud minority of gamers have always been super toxic (e.g. gamergate) but they hit peak levels of insanity when this incident.

It was actually the last straw for my reddit usage when I realized r/TheLastOfUs2 had been hijacked by people determined to censor any positive takes on the game. I've deleted the app and no longer visit the site and my mental health is already better for it.

What does Last of Us say about fungi?

In the beginning, Joel will have to move inside confined spaces, thick contamined air fully surrounding him. In order to protect himself, he will put on his old gas mask that he's been using for years. Somehow that's sufficient. The spores apparently don't contaminate his hair, his clothes, his backpack, his weapons. Once he's cleared the area, he simply takes off the mask and moves on.

So I'm not sure if anything of substance can be learned from this game.

"This Is Your Brain on Parasites" is a fantastic book on this - https://www.amazon.co.uk/This-Your-Brain-Parasites-Manipulat...

There arn't many such parasites for bigger animals. Toxoplasma is probably the only exception. There are some interesting arguments about why in https://www.gwern.net/docs/genetics/selection/2019-delguidic...

> There is a part of me that wonders if there are things (viruses/bacteria/funguses) which effect human behavior.

Ofc there are. For one, its well known that certain worms can affect kids in such way that they become hyperactive.

About Romans, they intentionally put lead in wine for the taste, I am not sure if they also used lead pipes or cups.

The word plumbing is derived from the Latin word for lead (plumbum). Latin dictionaries also list the word for lead as a synonym for pipe. I think they did use lead pipes.

Thanks, I never made the connection between the plumbum(lead is called plumb in my native language) and plumbing. Anyway to confirm this I done some searching and yes, romans)and others) had plumbing and running water and used lead pipes too(though the lead in wine gives you much more poisoning where pipes are toxic only in certain circumstances)

https://www.quora.com/Did-Roman-Byzantine-plumbing-extend-to...

https://en.wikipedia.org/wiki/Roman_lead_pipe_inscription

I also heard that Roman middle classes who couldn't afford silver used leaden plates to eat off of. As lead very quickly develops an airtight patina, this is much worse than plumbing (which after installation of basically never touched) because knives, forks and just general friction of handling the plates causes the Patina to be scraped off and the food to be exposed to lead.

Only for the record, lead pipes have been extensively used (for drinkable water) till well into the 20th century.

The inner surface of the pipes soon form a sort of lining that is normally not dangerous/poisoining.

The amount of lead now admissable in EU is 10 micrograms per liter, but - at least here (Italy) - until 2013 was 25 micrograms per liter.

Usually only in some particular cases (acidic waters and "stagnation" in the pipes) some relevant amounts of lead are transferred to the water.

Drinking or eating from polished lead tableware is another thing.

An old name for lead acetate is "sugar of lead". Guess they needed to sweeten their wine.

Looking at the replies to this comment, I can say you are correct on your last point.

One perhaps unintentional detail which makes that story realistic is that humans are the only species which processes sex and violence with the same part of the brain. In other words we are the only species prone to confuse sex and violence. It is one of just two sexual behaviors which are unique to humans (the other being we strongly prefer to do it in private).

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