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This is about toxoplasmosis. It is also known to increase the odds that an infected rodent will get itself eaten by a cat: Infection with T. gondii has been sh

This is about toxoplasmosis. It is also known to increase the odds that an infected rodent will get itself eaten by a cat: Infection with T. gondii has been shown to alter the behavior of mice and rats in ways thought to increase the rodents' chances of being preyed upon by cats. https://en.wikipedia.org/wiki/Toxoplasmosis https://en.wikipedia.org/wiki/Toxoplasmosis It can infect humans. It may be a risk factor for schizophrenia, OCD, bipolar disorder and other mental health issues. The evidence seems inconclusive at this time.

kekebo 5y ago
The change of rat behavior seemingly being based on inverting rats' aversion to cat odors into developing an actual attraction for them [0]. Robert Sapolsky's work is an abundant resource on the topic[1]. [0] https://www.pnas.org/content/104/15/6442 https://www.pnas.org/content/104/15/6442 [1] https://scholar.google.de/scholar?hl=en&q=sapolsky+toxoplasmosis https://scholar.google.de/scholar?hl=en&q=sapolsky+toxoplasm...
feketegy 5y ago
It's not that black or white though, more than 60% of the World population has been infected with Toxoplasmosis, yet you don't see people running towards lions at every corner. The path how the parasite infects rodents, then cats, then humans is very complex and not at all consistent, most articles on the Internet dumb it down way too much. This Youtuber has an awesome explanation on it: https://www.youtube.com/watch?v=rdlHNhrMw-A https://www.youtube.com/watch?v=rdlHNhrMw-A Also, his channel is translated from Hungarian, it's an awesome channel btw.
- TheSpiceIsLife 5y ago
  > yet you don't see people running towards lions at every corner. The headline says more reckless. I wouldn’t consider it a stretch to say some people are definitely more reckless. Whether there’s a causal link, I couldn’t say.
  - SuoDuanDao 5y ago
    There's a theory that toxoplasmosis, given it can transfer from cats to humans, is the reason for the 'crazy cat lady' stereotype. Certainly, cat owners I've known seem more likely to have 'attacks' of extreme aggression than the general population, and giving vent to that does seem like a 'risk' to our status in the community that most of us don't take. Then again, having that sort of temperament may make someone more suited to owning cats than other pets...
- ptha 5y ago
  The article described something specific that could be tested. I leave it to the scientist to design a similarly specific experiment for humans. Also the "reckless" behaviour exhibited by the cubs disappeared after there were older than 1 year: While uninfected cubs stayed an average of 300 feet away from lions, cubs that had Toxoplasma antibodies in their blood had ventured within an average of 142 feet from the predators, a dangerous proximity. These differences disappeared after the cubs turned one, perhaps because the survivors learned not to get too close to the felines.
  - trhway 5y ago
    so those infected survivors got much closer than the healthy ones and yet survived. Sounds like a [harsh] filter for the high survivability traits which may be beneficial for the population, and that may explain why the [susceptibility to the] infection hasn't been selected out.
    - Retric 5y ago
      Possibly, but luck isn’t an inheritable trait.
      - sitkack 5y ago
        It is in humans.
        rfreytag 5y ago
        ... according to Larry Niven.
        sitkack 5y ago
        And Rockefeller, Cargil, Rothschild ...
        eru 5y ago
- thinkingemote 5y ago
  > yet you don't see people running towards lions at every corner Oh, but you do see people running towards cats! They keep them indoors and feed them.
- User23 5y ago
  Perhaps in more complex organisms there is a more complex response to the pathogen? It could trigger any number of maladaptive behaviors in humans and it would be hard to know if it was the parasite or one of the many other unfortunate environmental factors of the modern world.
  - eru 5y ago
    It might even trigger adaptive behaviours.
- justshowpost 5y ago
  Toxoplasma is dormant in humans. What is really interesting – how human toxoplasma prevalence varies per country.
cortic 5y ago
I remember an Australian study that showed a significant increase in the likelihood of men with toxoplasmosis to be involved in car accidents. There was also something about women being more promiscuous when infected. I doubt the study had proper controls, so don't take it too seriously, but i would be surprised if toxoplasmosis had no effect on the human hosts behavior.
- is_true 5y ago
  Racing drivers should be tested for toxoplasmosis. I had toxoplasmosis and I drive a bit on the aggressive side.
DyslexicAtheist 5y ago
The Economist ran a piece some years ago claiming a link between countries with reckless driving habits and high rates of toxoplasmosis in the population (pointing to France as an example): https://www.economist.com/science-and-technology/2010/06/03/a-game-of-cat-and-mouse https://www.economist.com/science-and-technology/2010/06/03/... Trematodas are really interesting too https://www.newscientist.com/article/2129880-parasite-living-inside-fish-eyeball-controls-its-behaviour/ https://www.newscientist.com/article/2129880-parasite-living...

kekebo 5y ago

The change of rat behavior seemingly being based on inverting rats' aversion to cat odors into developing an actual attraction for them [0]. Robert Sapolsky's work is an abundant resource on the topic[1]. [0] https://www.pnas.org/content/104/15/6442 https://www.pnas.org/content/104/15/6442 [1] https://scholar.google.de/scholar?hl=en&q=sapolsky+toxoplasmosis https://scholar.google.de/scholar?hl=en&q=sapolsky+toxoplasm...

feketegy 5y ago

It's not that black or white though, more than 60% of the World population has been infected with Toxoplasmosis, yet you don't see people running towards lions at every corner. The path how the parasite infects rodents, then cats, then humans is very complex and not at all consistent, most articles on the Internet dumb it down way too much. This Youtuber has an awesome explanation on it: https://www.youtube.com/watch?v=rdlHNhrMw-A https://www.youtube.com/watch?v=rdlHNhrMw-A Also, his channel is translated from Hungarian, it's an awesome channel btw.

TheSpiceIsLife 5y ago
> yet you don't see people running towards lions at every corner. The headline says more reckless. I wouldn’t consider it a stretch to say some people are definitely more reckless. Whether there’s a causal link, I couldn’t say.
- SuoDuanDao 5y ago
  There's a theory that toxoplasmosis, given it can transfer from cats to humans, is the reason for the 'crazy cat lady' stereotype. Certainly, cat owners I've known seem more likely to have 'attacks' of extreme aggression than the general population, and giving vent to that does seem like a 'risk' to our status in the community that most of us don't take. Then again, having that sort of temperament may make someone more suited to owning cats than other pets...
ptha 5y ago
The article described something specific that could be tested. I leave it to the scientist to design a similarly specific experiment for humans. Also the "reckless" behaviour exhibited by the cubs disappeared after there were older than 1 year: While uninfected cubs stayed an average of 300 feet away from lions, cubs that had Toxoplasma antibodies in their blood had ventured within an average of 142 feet from the predators, a dangerous proximity. These differences disappeared after the cubs turned one, perhaps because the survivors learned not to get too close to the felines.
- trhway 5y ago
  so those infected survivors got much closer than the healthy ones and yet survived. Sounds like a [harsh] filter for the high survivability traits which may be beneficial for the population, and that may explain why the [susceptibility to the] infection hasn't been selected out.
  - Retric 5y ago
    Possibly, but luck isn’t an inheritable trait.
    - sitkack 5y ago
      It is in humans.
      - rfreytag 5y ago
        ... according to Larry Niven.
        sitkack 5y ago
        And Rockefeller, Cargil, Rothschild ...
        eru 5y ago
thinkingemote 5y ago
> yet you don't see people running towards lions at every corner Oh, but you do see people running towards cats! They keep them indoors and feed them.
User23 5y ago
Perhaps in more complex organisms there is a more complex response to the pathogen? It could trigger any number of maladaptive behaviors in humans and it would be hard to know if it was the parasite or one of the many other unfortunate environmental factors of the modern world.
- eru 5y ago
  It might even trigger adaptive behaviours.
justshowpost 5y ago
Toxoplasma is dormant in humans. What is really interesting – how human toxoplasma prevalence varies per country.

cortic 5y ago

I remember an Australian study that showed a significant increase in the likelihood of men with toxoplasmosis to be involved in car accidents. There was also something about women being more promiscuous when infected. I doubt the study had proper controls, so don't take it too seriously, but i would be surprised if toxoplasmosis had no effect on the human hosts behavior.

is_true 5y ago
Racing drivers should be tested for toxoplasmosis. I had toxoplasmosis and I drive a bit on the aggressive side.

DyslexicAtheist 5y ago

The Economist ran a piece some years ago claiming a link between countries with reckless driving habits and high rates of toxoplasmosis in the population (pointing to France as an example): https://www.economist.com/science-and-technology/2010/06/03/a-game-of-cat-and-mouse https://www.economist.com/science-and-technology/2010/06/03/... Trematodas are really interesting too https://www.newscientist.com/article/2129880-parasite-living-inside-fish-eyeball-controls-its-behaviour/ https://www.newscientist.com/article/2129880-parasite-living...