Starting in the early 1990s, he began to suspect that a single-celled parasite in the protozoan family was subtly manipulating his personality, causing him to behave in strange, often self-destructive ways. And if it was messing with his mind, he reasoned, it was probably doing the same to others.The parasite, which is excreted by cats in their feces, is called Toxoplasma gondii (T. gondii or Toxo for short) and is the microbe that causes toxoplasmosis — the reason pregnant women are told to avoid cats’ litter boxes.

How Your Cat Is Making You Crazy in The Atlantic. Don’t worry, it has a happy ending.

12 thoughts on “Cats Make You Crazy

  1. Despite having had cats her entire life (at least a dozen, indoor and outdoor), and even having worked extensively with tigers, lions, servals, jaguars, leopards, bobcats, etc, my wife tested negative for Toxoplasma gondii during her last pregnancy.

      1. Catcha! (Clever one, Matt.)


        P.S.: Congratulations on being FPed! Oh, wait. You voted for yourself! Or could have. Nah, I’m just taking the mick. Nice work. Seriously. Skip the stickers. But stickers tell stories. Right, it’s *your* toy. *Your* choice. I’m outta here.

  2. My Goodness! That’s a great article. I always knew that there was something evil about cats. I kid, of course, though I am a dog guy. Just another reason for me to avoid cats, if I needed one. If my allergies, their claws and their aloof demeanor were not enough reason now I can add mind altering parasites to the list. Funny…I just perused a web site yesterday that listed all the ways that those zombie movies and disease movies like “28 days” could actually happen and the cat poop parasite didn’t even make the list. I should have guessed that simply clawing up the furniture would eventually bore them. Look out!

  3. Tissue cysts are ingested by a cat (e.g., by feeding on an infected mouse). The cysts survive passage through the stomach of the cat and the parasites infect epithelium of the small intestine where they undergo sexual reproduction and oocyst formation. Oocysts are shed with the feces. Animals and humans that ingest oocysts (e.g., by eating unwashed vegetables) or tissue cysts in improperly cooked meat become infected. The parasite enters macrophages in the intestinal lining and is distributed via the blood stream throughout the body.

    Similar to the mechanism used in many viruses, Toxoplasma is able to dysregulate host’s cell cycle by holding cell division before mitosis (the G2/M border).[5] This dysregulation of the host’s cell cycle is caused by a heat-sensitive secretion (with a molecular mass larger than 10 kDa).[6] Infected cells secrete the factor which inhibits the cell cycle of neighboring cells. The reason for Toxoplasma’s dysregulation is unknown, but studies have shown that infection is preferential to host cells in the S-phase and host cell structures with which Toxoplasma interacts may not be accessible during other stages of the cell cycle.

  4. It should be said that toxo usually affects immunocompromised people so it’s recommended that litter boxes be scooped daily. Immunocompromised people can have their health affected just as negatively or worse by being around sick children and adults. People can also get toxo from eating raw and undercooked meat. Cats are wonderful and affectionate animals. I hate seeing things like this be the basis for peoples’ opinions of them. Please read this article for more information.

  5. Hello Brewster Smith,

    >I always knew that there was something evil about cats.
    – From one doggone crazy person to another um, do lover – bow wow! But I would suggest you don’t get too comfortable with the thought of Lassie sporting a halo.

    This is what a friend sent me because he knows I’m barking mad about pooches:

    >I kid, of course, though I am a dog guy.
    – Me, too! Except I’m not a guy. Also, much as I wave my ‘Dogz rule!’ freak flag, I love all animals.


  6. Hi Matt.

    I’d just like to say (and I know this probably isn’t the best of places to say it!), this is the coolest website I have ever seen in my entire life. First of all you google Matt, and you come up second… I mean get out that’s ridiculous.

    But seriously this website stands out so much great job 🙂