Is your cat making you nuts?

February 12, 2012 • 1:04 pm

If you like cats, have a cat, or are simply interested in a superb popular science piece, do read this article in The Atlantic by Kathleen McAuliffe: “How your cat is making you crazy.” It’s about new research on the disease toxoplasmosis, caused by infection by the protozoan Toxoplasma gondii (here it is):

The primary host is, sadly, kittehs, and the oocysts (tough spores containing the zygote) are passed on in cat feces, which can go on to infect other species, including humans.  (This is why pregnant women aren’t supposed to handle cat litter, though the disease is limited to cats who go outside.)  Here’s the life cycle, complete with an evil-looking cat (for which I apologize):

Anyway, you may know of new research suggesting that the parasite itself can manipulate rodents to make them more susceptible to cat predation. Infected rats or mice not only show less fear of cats, but are even attracted to the scent of cat urine, which normally repels them.  This may be one of those fascinating cases in which a parasite takes over the behavior of its host to further its own transmission. (When a cat eats an infected rodent, it gets infected itself, an essential step in the parasite’s life cycle.)

McAuliffe, however, dwells on new findings that humans infected with toxoplamosis—and there are many of us, about 30% of the world’s population—may show subtle behavioral changes, or even drastic ones.  She notes that the incidence of infected people is more than twice as high among involved in traffic accidents than among people in a non-accident control group, and she cites research showing that infected human males tend to dress more slovenly than those who are non-infected (those males also show a higher attraction to the scent of cat urine). In contrast, infected women dress more meticulously.  Finally, there may be a connection between Toxoplasma infection and schizophrenia, though the data are very preliminary.

I recommend this article highly: it’s really well-written and full of intriguing information.  It’s the paradigm of what a popular science piece should be, and I hope McAuliffe, whose website is here, produces more of these.

39 thoughts on “Is your cat making you nuts?

  1. That is interesting; perhaps this explains why people keep cats as pets – we are attracted, like rodents, by cat urine (although I recall it as fairly foul, myself). I was raised around cats and am not the neatest of males, by far, fairly casual and not to tidiness oriented, but I don’t recall my mother or sister by be any means meticulous, so not much data here. My brother is a complete mess, but doesn’t keep or like cats, so not much help on this hypothesis there either.

    Still if a parasite can manipulate one mammal for its benefit why not another (and surely being a parasite on a warm fat healthy long-live pet has got to be a better living than on a feral cat)

    1. Ha ha!

      My family are all dog lovers – and some are even cat-haters – my father, brothers and myself are disasters in term of clothing, and my only sister is very fashionable (she is a pet-hater, being bitten by a dog in his teens).

      So, are we cursed by ceiling-catz to become forced slaves (instead of willing subjects) ?


  2. A fascinating and rather alarming article. A friend of mine lost the use of one eye to Toxoplasma gondii, and another lost her sister to schizophrenia so this is rather close to home. To say nothing of my lovely floofy kitteh, who now looks a bit more menacing!

  3. So, if you’re a gay man and you need to worry about not catching this disease, just only date the other well-dressed gay men, and don’t hang out with any who enjoy the smell of urine! =^_^=

    Lesbians, well, stay away from the lipstick ones!

    Thankfully, my kittehs are hostage (indoor only) kittehs, and we keep anti-mouse-attack equipment armed at all times. (Though, the first line is trap and release rather than kill.)

  4. Hmm…this is perfect for hypochondria. I’m kind of dressed down today and it leaves me wondering if I have parasitical brain infection :-0

    But where are all the photos of meticulously dressed cat ladies? I think the Simpsons may need to update their drawing model for Agnes, the crazy cat lady.

  5. So the ‘Doritos dog’ was saving his master? (sorry, I’m one of those sicko dog people who found the add funny – dogs make deals, cats give you diseases that make you crazy…) (and just for the record, I do like cats too. My sense of humor is just a bit on the warped side)

  6. I love that last line:

    I may have dodged T. gondii, but given our knack for fooling ourselves—plus all those parasites out there that may also be playing tricks on our minds—can anyone really know who’s running the show?

    Take THAT, free will! I think this sort of research is more persuasive for the argument against free will than the reaction-time ones. How can a person be said to have free will when the application of a parasite can change the outcome of the processing of information in the brain? The thing is, without knowledge of the infection, the person will still feel that they are in control, and making those choices of their own free will.

    1. Hmm…perhaps the talking snake that persuaded Eve to eat the fruit of the Tree of Knowledge was actually a *metaphor* for Eve’s Toxoplasma infection?

      Quick, to the Accomodationmobile, someone call Karl Giberson!

  7. Now that’s the way science should be written up for the general public: Clear, clean, concise, understandable, accurate, and fascinating.

    A stray thought: I wonder how many Republicans have cats? Sure would explain their tortuous “thought” processes…

  8. Toxo allegedly alters behaviour too – the high road accident rate may reflect risk-taking rather than, say, clumsiness

  9. Oh, and to answer the post title. It doesn’t take a parasite to have your cat make you nuts! That’s a natural cattribute.

  10. Carl Zimmer had a blog post on this a number of months ago. I posted it on Facebook and all my friends insisted they were not going to shake my hand anymore unless I washed them repeatedly.

  11. From the article:

    “y. Compared with uninfected men, males who had the parasite were more introverted, suspicious, oblivious to other people’s opinions of them, and inclined to disregard rules. Infected women, on the other hand, presented in exactly the opposite way: they were more outgoing, trusting, image-conscious, and rule-abiding than uninfected women. “

    Since atheism can involve being suspicious of and going against the status quo, I wonder if infection also correlates with higher degrees of atheism for men? And if women become more trusting, I wonder if that correlates to higher degrees of religiosity and/or susceptibility to woo?

    1. “… suspicious, oblivious to other people’s opinions of them …”

      This doesn’t sound right to me. “Oblivious” as in carefree, or as in wrong?
      Wrong sounds compatible with suspicious.

  12. Does it affect our minds? Does it rob us of free will? I don’t know about you but I, for one, welcome our whiskered overlords.

  13. When I was reading the Atlantic, I realized that the article was describing my wife and me precisely. We’ve always been cat lovers. Great. The only thing worse than going crazy is knowing you’re going crazy.

    1. You are becoming less attired but more attractive to ladies, while your wife becomes more fashionable and more attracted to you ?

      Indeed a form of ceiling-catz nirvana!

  14. those males also show a higher attraction to the scent of cat urine

    So lemme get this straight (you put da lime inna coconut): control mode is attraction to cat urine. Once infected, the attraction is greater?

    Anyway, if anyone wants to test this without resort to collecting feline urine, the scent is easily approximated by mercaptoacetic acid.

  15. To you all ceiling-catz adherents, beware for this LOLapocryphaz! These texts are from those that hates ceiling-catz, similar to those mo-cartoonists to moslems! No-truth except the drive to lessen the meowness of your-highness!


  16. Anyone know what proportion of cats have T. gondii, whether there are any activities that make them more likely to become infected, and how likely it is that a human owner will become infected?

    I’m not normally very hypochondriatic but I found this article a little alarming…

  17. I’ve been fascinated by toxoplasmosis since I first learned about it. I’ve had it on my House Challenge list over at Polite Dissent for the past 3 years, but have yet to score a single point of it.

    I’ve nearly always owned at least one cat (and currently have one not particularly bright cat), but I’ve though that this would make the basis of an interesting science fiction story: the parasite affects our brains in such a way to make us like cats, and this is the only reason why anyone keeps cats as pets.

      1. Hey, they can’t all be above average. My cat helps all the smart cats look better.

        I’ve tried to get my cat to understand that if she wants to convince me she caught a mouse by delivering the corpse to my bedroom floor, she needs to take the mouse out of the trap first.

        1. That’s the thing about Cats, Ceiling Cat has endowed them with the ability to all be above average. Ceiling Cat works in mysterious ways, and one cannot know the the mind of Ceiling Cat.

          Out of the trap. lol

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