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This is fascinating and horrifying. I often wonder if there are parasites we doing know about that affect human behavior.
There are! One of the most dangerous is forcing you to write the word "doing" in places it makes no sense!
Pretty sure they meant "don't know about" in the phrase you're referring to. Perhaps they were posting from a portable "smart" device and got caught out by the ever so reliable "auto-wrong" system, or maybe they just had a "brain-fart" while typing fast…
As someone mentioned, Toxoplasmosis is one. We also know that your gut bacteria produce exudates that affect mood, sleep and other things.
One has to treat their housemates in the gut well to sleep well it seems. :)
Or clean house.

It's uncomfortable for sure, but you'll live through it - they won't. Get better tenants.

I won't be sleeping well tonight.
I think this shows that we are just a "chemical machine" with no soul or will of our own.
>I think this shows that we are just a "chemical machine" with no soul or will of our own.

My particular mix of parasites tells me to say that there is no soul, but free will does exist.

> ...there is no soul, but free will does exist.

This is an interesting one, depending on whether you subscribe to the beliefs that the universe is deterministic or not. If determinism were to be truly possible, then technically with enough information you could predict what is going to happen next, what anyone is going to think, say, do etc.

In that case "free will" wouldn't be an entirely correct description. Then again, even if that were to be true, the amount of processing power to see how this "preordained" sequence of events would play out might be orders of magnitude more than laws of physics might permit, making it all a bit of a moot point.

That said, there was a cool science fiction story about the concept, "What's expected of us": https://www.nature.com/articles/436150a

Of course, I doubt whether "free will" being real or not would matter that much to people in actuality.

For example, my current understanding of the world makes me feel that once I eventually die, there will be nothing after that and I'll cease to exist. A moment in which my consciousness will exist and then another one in which it will no longer do so and will never do so, until the heat death of the universe (it won't matter to me then because there won't be a "me", but knowing that whilst being alive is the most horrible thought ever).

It's quite dreadful, yet somehow I still get up for menial programming work every morning. :')

My parasites only allow me to say "My particular mix of parasites tells me to say that there is no soul, but free will does exist" and "My parasites only allow me to say 'My particular mix of parasites tells me to say that there is no soul, but free will does exist'."
My current state tells me that neither soul nor free will are possible in a closed system regardless of probabilistic events.
My question is, what does "free will" even mean?
I have the same question. Definition from Wikipedia "Free will is the capacity of agents to choose between different possible courses of action unimpeded." If your actions and decisions are a result of chemical and electrical activity in your brain, it does still mean that you are in control and unimpeded.

Free will seems to exist in a middle state where you do not think of yourself as a soul separate from your physical form and where you accept yourself as a carbon based organism reacting to processes.

Who is supposed to have this free will?

strange no mention of facebook, instagram or tic tac, even though they fit the description
their hosts are datacenters, not their users
I sometimes (jokingly) wonder whether extreme rock climbers like Alex Honnold have a species-jumping parasite that makes them want to reach the highest point around. Something similar to this worm (1) that infects ants and makes them climb to the top of blades of grass, where they are more likely be eaten by an ungulate, thus allowing the parasite to move to the next stage of its reproductive cycle.

1) https://www.popularmechanics.com/science/animals/a21248947/b...

I'm surprised that Toxoplasma wasn't discussed.

It's associated with risk taking in humans. It'd be interesting to see if VCs ever start screening for it.

From this article: https://pubmed.ncbi.nlm.nih.gov/31980266/

A more recent study shows that toxoplasma infection prevalence was a consistent, positive predictor of entrepreneurial activity.

> I'm surprised that Toxoplasma wasn't discussed.

> It's associated with risk taking in humans. It'd be interesting to see if VCs ever start screening for it.

Since first reading about that one years ago (and how it's believed that a ridiculously high percentage of humanity is probably already infected with it), I've often wondered if it doesn't maybe explain at least some of the insanity that we see happening in the news so frequently. Perhaps we should add a new requirement to being able to hold a "leadership" position in society that you be screened for and certified clear of brain altering parasites?

I didn't see any study demonstrating that Toxoplasmosis alters the brain of humans. Do you know any to share?

The "entrepreneurial tendency" is just a correlation.

We need to be careful in drawing such conclusions, especially when we call for broad societal changes based upon them.

> "I didn't see any study demonstrating that Toxoplasmosis alters the brain of humans. Do you know any to share?"

I've never yet seen any such study yet myself, but I know there's been studies enough on how it affects the brains of mice, and given that it destroys the mouse's "risk aversion" such that the mouse will basically feed itself to a cat (to complete the life cycle of the the parasite), one might wonder if it has a similar effect on the risk aversion portion of the human brain as well… Seems to me that if no proper studies have yet been done on that, then perhaps such studies should be done, considering a significant portion of humanity likely already has this parasite happily eating away at their brains, including probably most of our "leaders".

We have to be careful in differentiating correlation and causation.

The study seems to show a correlation only, not establish causation. It seems to me you might have read it as causation (?).

Perhaps what is at play is that people who already have entrepreneurial tendencies end up exposing themselves to being infected more often than the average population.

I chose the word associated very deliberately. It's hard to show causation in humans for ethical reasons.
Given that toxoplasmosis has been clearly shown to cause behavioral changes in rodents [1], and there's even an evolutionary explanation that shows why this behavioral changes is advantageous to the parasite, it's not unreasonable to think it's more likely that the behavioral differences seem in humans are also caused, not simply correlated with, the parasite.

1. https://pubmed.ncbi.nlm.nih.gov/20608470/

the ant thing. So.. I get "close to the nest so it infects other ants" but .. is this not just statistics doing what darwinism does? if the fungus infects an ant far away, it has less outcome on the infection rate. the statistics of random chance infection ultimately favour the variances in the fungus, which produces more infection "close" to the hive. It has specific infectability, periodicity, plays to the ants day/night patterns, because its "more fit" statistically it skews to higher reproduction.

I much prefer a statistical model and skew, to intentionality language. maybe its me.

You're right. In fact, most write-ups on Darwinism (and evolution in general) incorporate too much intentionality in their tone when there might be none.
Have you ever tried writing about this topic? It’s surprisingly hard to keep intentionality out if you’re trying to give meaningful explanations.
I think about this a bit. I had the temerity to try and write to Dawkins about this some time ago. I think I got a sense of "yes, given the chance, I think use of more statistical language would have been beneficial, but none of us realized how strongly the intentionality would be misunderstood" in reply, but I can't find the emails so I suspect I may have mis-remembered.

Really I'd like to ask it face to face. For the experience.

And yet you use intentional language when talking about yourself, but humans are just another set of biological machines subject to Darwinian evolution. Where do you draw the line?
Is it wrong to think of marketing akin to parasites that affect behaviour? Often they say "sex sells", isn't that something that often uses images that humans are pre-programmed to desire alongside the product that marketing want to shift. I don't think this is a new concept, but perhaps I've just had an epiphany.
> Is it wrong to think of marketing akin to parasites that affect behaviour? Often they say "sex sells"...

I've long believed that the evolution of sexual reproduction is a kind of parasitic virus. Just consider the case of humans: the perfectly good string of X chromosomes are slightly modified in the parasitic version (one is stunted, and alters the development). The parasite uses a variety of ways to lure a host.

The parasite then literally injects its DNA into the normal host, causing it to generate either new hosts or parasites, doing all the work without further action by the parasite, spreading the parasite's own DNA into further generations of host and parasite.

Kind of hideous to think of it, but it does seem likely that at some point science will find a way to retain the benefit of gene mixing without requiring the parasitic form, and the scourge will be eliminated from humanity.

As amusing as this is to read (you went to a frankly incredible amount of effort to make this sound disturbing and to my mind you absolutely succeeded), the emotion is somewhat muted by not being able to figure out whether or not you are serious. I guess you could say this is part of it. Very nice.
While that's an interesting perspective, the argument is diminished by the fact that sexual reproduction existed long before internal fertilization, so there was no "injecting" for the first 1.5 billion years of sexual reproduction.
Well, those early eukaryotic mixings did involve an exchange of genetic material though perhaps it was less "injection" than letting things drift back and forth between the two cells for a while.

Of course by then viruses were already busy doing their genetic injection thing, but we tend not to consider it sexual, even though it is reproduction. Humans love to be bigoted about these kinds of distinctions!

What if viral and parasitic reproduction is different and produces a "Clone" instead of an "Offspring" ? That would explain so much about how these things seem to work as one.

Either that or there HAS to be a form of distributed communication technique here that we haven't yet discovered.

I was a little disappointed to see no mention of Bracovirus and Ichnovirus, two related but otherwise effectively unique genera which constitute the family Polydnaviridae and which are intimately symbiotic with parasitoid wasps of families Braconidae and Ichneumonidae.

These viruses' genomes are actually incorporated into those of the wasps, and are thus passed on from mother to daughter. The virus doesn't circulate in the body of the wasp; instead, female wasps' ovaries include a unique type of cell which is specialized to act as a viral replicator, generating and storing virus particles from the relevant sections of the wasp's own genome. When the mother wasp injects an egg into its caterpillar host, she secretes a dose of virus along with it. The virus serves to suppress the host's immune system and physical development, and in some cases also modifies its behavior, in order to ensure a favorable environment for the baby wasp's development.

No one, or at least no one I've yet read, knows of any other example in nature of such a close mutualism. No one knows when or how it evolved, or where Polydnaviridae fits into the larger taxonomy of viruses. It's just a shame they weren't discovered in time for Dan O'Bannon to incorporate them in the screenplay for Alien, which already takes considerable inspiration from the reproductive habit of spider wasps; it'd be a different film, and I think perhaps an even better one, for the inclusion.

> No one, or at least no one I've yet read, knows of any other example in nature of such a close mutualism.

Personally I found the relationship b/w fig trees and fig wasps quite amazing and extra-ordinary when I, for the first time, watched a documentary on this subject.

You can check it out here: The Queen of Trees - https://www.youtube.com/watch?v=xy86ak2fQJM

Oh, I'm well familiar, although I admit most of my fig-tree-related wasp interest has to do with larger animals such as this [1] European hornet who graciously tolerated my camera flashes for a brief while the other day. Lots of animals come late in the season for fruit still on the tree, which is both nutritious and intoxicating due to the ethanol produced by fermentation - that said, this was the first year I've met a hornet there, more usually seeing bald-faced yellowjackets [2]. (And likely the last, unfortunately, unless I'm able to form a good enough relationship with the new owners here that they'll likewise put up with my camera flashes once or twice a year.)

[1] https://aaron-m.com/wp-content/uploads/2022/09/img_0826.jpg

[2] https://aaron-m.com/wp-content/uploads/2022/09/img_0821.jpg

A big take here is how similar are the brains of almost all animals in existence.

It's not only parasites, you also have viruses. Rabies, for example, manipulates the brain to induce what to me appears to be a highly specific response to a very specific thing : hydrophobia (see https://en.wikipedia.org/wiki/Rabies#Signs_and_symptoms , in particular the video).

And it induces the _same_ symptoms on a huge chunk of mammalian species. For all you think the human brain is different from that of say, a wild fox, the same mechanism used by this virus to introduce hydrophobia _works_ on both species' brains.

It's already amazing to me that you can manipulate different human brains in the same way and introduce such a specific response; the idea that it would even extend to different species... If you believe even for a second that brains work in any way like a neural network, this is just mind-boggling. How can you manipulate a neural network to suddenly fear water? How can you manipulate _different types of neural networks_ to suddenly fear water, in a generic way? You/the parasite/the virus can only influence the hardware/wetware, and not what the NN is trained on.

It's evident that it's not an easy task, not even for the virus itself, as it "fails" to work on around 20% of the infected, as per the wikipedia article, where it causes some strange lethargic behavior instead of the "intended" waterphobia. ("Intented" because it's definitely more likely to cause the virus to propagate than the lethargic behavior).

Well, the brain is not a back-prop NN, that's obvious. It's also obvious that a part of it is pre-wired for essential "life support", such as generating a heart beat, breathing, walking, sucking, etc. It's interesting to consider how deeply instinctive our knowledge of water is, but since our lives depend on it, I suppose quite deep, and thus related to that of other mammals.
> How can you manipulate a neural network to suddenly fear water? How can you manipulate _different types of neural networks_ to suddenly fear water, in a generic way?

These kinds of reactions, and the many hyper-specific adaptations across the animal kingdom, make me think our current model of life lacks the entropy required to account for the behavior we see. It's like in a movie when they tell the geek to do some highly complex and customized task, and he clicks a couple keys and it's done.

> Rabies, for example, manipulates the brain

I'm not sure that's a brain manipulation, but rather rabies making it traumatically painful to swallow, mixed with a tortuously deep thirst.

It's more than that.

See this rather disturbing video of someone with rabies trying to take a drink: https://www.youtube.com/watch?v=OtiytblJzQc

They do not just try, they succeed. It's disturbing because you can be sure this is a person who is dead now (and this was the process of them dying), but being able to take a drink is impressive.
I've experienced this with liver flukes (fasciolosis). I've always been strong, quite confident, fit and healthy. But gradually over a period of 18 months or so I was experiencing chest pain in the right upper quadrant, binge eating (sugar / sweets) and ultimately had a panic attack or two. I was agitated, exhausted and a somewhat fearful. I felt like I might die and I made the necessary plans for that. Altogether a dramatic departure from my former "self".

Thankfully some googling of symptoms got me on the right track, I got the medicine and got that nasty thing out (it took 12 months to get fully rid of them). Full body health checks, ultrasound, MRI, doctors, specialists all failed to diagnose this not so rare parasite. Lucky for me but sad for those who aren't likely to find the answers I did. Some others have had gall bladders removed due to false diagnosis of cancer due to dilation of the gall duct.

I certainly feel they manipulated me to consume what was beneficial to them. Fortunately they made the mistake of not being stealthy enough. Perhaps they where too greedy for growth. Absolutely fascinating.

>Full body health checks, ultrasound, MRI, doctors, specialists all failed to diagnose this not so rare parasite.

How did they find it in the end? Or did they just give you some broad antiparasitic. ?

They didn't find it.

Triclabendazole is only one effective treatment for fasciolisis. It's on the WHO list of essential medicines.

Unfortunately a prescription is needed where I live and that country does not have the diagnostic test.

More info [1] on two cases here where one woman had her gall bladder removed after being misdiagnosed cancer.

How did I treat it? I ordered the medicine for dogs, cats and took the leap of faith. Now that's probably considered incredibly stupid and reckless by some but I had 100% symptoms relief within 48hrs followed by some die off. I followed protocol and did a second round of medicine 6 weeks later.

This was during covid so I had no way to fly to a country that offered the diagnostic test.

[1] https://www.mja.com.au/journal/2015/203/4/fascioliasis-austr...

Oh, wow, I'm really happy for you making this.

I'm wondering why these diagnostic tests aren't more common. After all for pets we have routine checkups.

I'm wondering if there's any imaging technique that could reveal this. I saw one House episode where they had a similar case, and they also went through 5 different imaging techniques until they found it.

The blood test isn't cheap and the parasite is prevalent in poorer tropical countries. Its suspected there are over 500k undiagnosed cases in Indonesia alone. I feel for those poor folks. Its often in cattle and the grass of pastures. But liver flukes have made there way to the sea and can now be caught by eating pelagic fish raw like tuna sashimi.

Regarding imaging yes. Ultrasound of the liver can detect it but requires a technician with very specific training to identify it and depends on the stage of the infection. Ultimately AI could be a solution. But as that original article demonstrates, even doctors and ultrasound technicians at world class hospitals can misdiagnose the issue as cancer.

If I had more knowledge in the field I would love to develop a project to reduce the cost of diagnostics to less than $10 and make treatment more available.

Trestment should not be out of reach of underprivileged.

>If I had more knowledge in the field I would love to develop a project to reduce the cost of diagnostics to less than $10 and make treatment more available.

If it's an antibody test, couldn't we repurpose all these facilities manufacturing COVID tests? They manufactured quick tests for 1€ a pop.

I expect this business to need something new to focus on, since COVID won't matter in the medium term anymore.

I think many many people are infected. Is it not interesting that only humans are never given antiparasitic drugs on a schedule?