8 ms·

How Your Cat Is Making You Crazy

182 points by kawera 15y ago

marshray 15y ago
Finally! A scientific explanation for http://www.youtube.com/watch_popup?v=sP4NMoJcFd4 http://www.youtube.com/watch_popup?v=sP4NMoJcFd4 !
kqr2 15y ago
For people with cats, some reassuring text: Given all the nasty science swirling around this parasite, is it time for cat lovers to switch their allegiance to other animals? Even Flegr would advise against that. Indoor cats pose no threat, he says, because they don’t carry the parasite. As for outdoor cats, they shed the parasite for only three weeks of their life, typically when they’re young and have just begun hunting.
- draggnar 15y ago
  hmm not so reassuring...
  - batista 15y ago
    Are you kidding me? Besides the "Indoor cats pose no threat, he says, because they don’t carry the parasite", what other kind of reassurance you want? Not to mention the fact that people seem to live on fine with domestic cats for the last 2,000 years, with no casualties...
    - jakeonthemove 15y ago
      It also kind of explains the pyramids... it wasn't aliens, it was cats! :-)
      - Rariel 15y ago
        I know humor is sort of frowned up on HN but that was hilarious.
        tripzilch 15y ago
        Downvoted for enjoying yourself.
    - ben0x539 15y ago
      Of course the author says that! He has cats, he must be infected too! But seriously, the claim wasn't that the parasite immediately kills people but makes them more disposed towards self-destructive behavior. The fact that, 2000 years after people started living with cats, humanity yet survives isn't really absolute proof to the contrary.
      - goblin89 15y ago
        Well, article claims that people really have started living with cats (that is, keeping them as pets) since 18th century in France, which is also when schizophrenia started to spread. So yeah, just over a century later and by the looks of it humanity is lucky to still survive! Imagine how different life would have been now without that crazy infected folk who like dangerous driving and become obsessed with insane ideas. =) By the way, can anyone clarify—is there a way to detect toxoplasmosis even in latent form? It seems from Wikipedia article that blood tests can't provide reliable results here.
      - draggnar 15y ago
        Maybe we have evolved with the influence of cats, who are really in power. They use us to achieve their objectives (mining for gold for some reason maybe?). The toxins keep us under control. It makes so much sense!
    - draggnar 15y ago
      Because i have an outdoor cat! When it was a kitten it would go outside hunting. And it wants to kill me.
rsanchez1 15y ago
Looks like there is something to the "crazy cat lady" after all.
- commieneko 15y ago
  Except the supposed behavior alteration in women is increased social activity, attention to appearance, neatness, and aversion to the smell of cat urine.
  - gojomo 15y ago
    Average alteration. Given the article's suggestion that some people react differently to infection (as in the schizophrenia/immune-system discussion, and not just by gender), plus the similarity of cat ladies' behavior with infected rats in some dimensions, a link between this parasite and the 'cat lady' archetype is not an outlandish conjecture.
ryan-allen 15y ago
There's more information on this parasite on Wikipedia: http://en.wikipedia.org/wiki/Toxoplasmosis http://en.wikipedia.org/wiki/Toxoplasmosis Other links on the 'net that I've found are reporting (without any citations) that the parasite can be detected with a blood test (according to wikipedia, not true) and that it cannot be treated (again, according to wikipedia, also not true). I've seen articles about this parasite pop up over at least the last 5 years. If it was a truly serious problem I'm sure there'd be more information about it. It smells a bit like FUD though. Can anyone else elaborate on this further?
- Alex3917 15y ago
  "If it was a truly serious problem I'm sure there'd be more information about it." That's not really how science/epistemology work.
- Game_Ender 15y ago
  WebMd [1] and some other places [2] talk about it like it's a bacteria that your immune system fights off then you are safe from for the rest of your life. They don't seem to talk about any long term effects, and focus on just the risk the acute symptoms can have. [1] http://www.webmd.com/food-recipes/food-poisoning/toxoplasmosis-test http://www.webmd.com/food-recipes/food-poisoning/toxoplasmos... [2] http://www.pamf.org/serology/clinicianguide.html http://www.pamf.org/serology/clinicianguide.html
- yew 15y ago
  Five years isn't all that much time as far as bio-med research is concerned. I would expect to start seeing definite results in maybe a few years. As for detection and treatment, the subject being discussed in the Wiki article is the effect of initial infection. The parasite sticks around in a latent form after being "fought off" and is being hypothesized to have additional long-term effects.
- Read_the_Genes 15y ago
  A search for Toxoplasmosis on G-scholar reveals that this parasite is in fact a problem for immune compromised patients and infants. Although I do not think WebMD is a reliable source, another comment here cites them to indicate that infections are usually cleared up by our immune system. This appears to be plausible, but because the parasite enters cells, and can hide in a latent phase, your immune system may be unable to clear the infection permanently. Because the parasite can halt the cell cycle, it may be able to hide indefinitely. I would not be concerned about a latent parasite, but its re-emergence may become a problem if your immune system becomes compromised. A correction to your statement that, according to wikipedia, the disease cannot be tested by blood sample. Wikipedia, in fact, stats that it can be tested by blood or other tissue, but only if the parasite is active (non-latent). Regarding its effect on behavior, the parasite seems to increase dopamine levels and possibly inhibit fear response. Since the increased dopamine is caused by an enzyme made by the parasite, this probably only occurs during a full scale infection. The inhibition of fear may occur while the parasite is inactive, if the parasite is able to enter cells in your amygdala. I do not see this inhibition of fear as long-lasting, except perhaps in extreme cases. One disclaimer, I grew up with a few cats, so I may have been, or am currently, infected. I cannot rule out that this parasite is manipulating me to write this comment. Now I'm off to find some cat pee. Can't get enough of that smell, mmmmmmmm..... More technical wiki article: https://en.wikipedia.org/wiki/Toxoplasma_gondii https://en.wikipedia.org/wiki/Toxoplasma_gondii
genbattle 15y ago
This is a repost of an earlier submission at http://news.ycombinator.com/item?id=3573447 http://news.ycombinator.com/item?id=3573447 (It was probably posted previously before that)
jlees 15y ago
Here's a thought. Helen Fisher's research categorises people into four dominant personality types based on levels of neurochemicals: http://socionist.blogspot.com/2009/04/helen-fishers-types-explorer-builder.html http://socionist.blogspot.com/2009/04/helen-fishers-types-ex... For dopamine, which according to the cat article is elevated in Toxo-infected humans, the associated personality type is "risk-taking, curious, creative, impulsive, optimistic and energetic". Plus the associated decrease in fear response in rats: who does that sound like? i.e. I wonder what percentage of entrepreneurs are Toxo infected?
- abecedarius 15y ago
  Your question reminds me of a word one of my programs coined: entrepreneuropsychology.
- rflrob 15y ago
  Here's the question, though: are the risk-taking humans risk-taking because they're infected, or are they infected because they're risk taking. Correlation, unfortunately, doesn't imply causation. The "fatal attraction to cat urine" studies are somewhat imperfect [1]. I'm friends with a student who's doing similar studies with mice but with better spatial discrimination . The consensus seems to be that while the fear response goes down, the idea that it's attractive to the rodents is more difficult to replicate. [1] Free at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1690701/?tool=pubmed http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1690701/?tool=pu...
clutchski 15y ago
I loved this talk on Toxo and its effects on freewill by the always incredible Robert Sapolsky. http://www.edge.org/3rd_culture/sapolsky09/sapolsky09_index.html http://www.edge.org/3rd_culture/sapolsky09/sapolsky09_index....
spacemanaki 15y ago
Radiolab delved into this a bit in their show "Parasites" from a while back. You can listen to the relevant segment under "The Scratch", although I recommend the whole thing, of course: http://www.radiolab.org/2009/sep/07/ http://www.radiolab.org/2009/sep/07/
sakura_k 15y ago
This dude knows nothing about cats and crazy. Cats make you crazy by pawing your face all night for attention and sleeping all day because they're tired from being awake until dawn.
- zalew 15y ago
  hahaha, word. What makes you crazy is that cat wants attention when you are busy or sleepy and wants you away when you want to pet it, screams and breaks stuff when it's hungry and scratches your furniture. and this http://www.doggiestylish.com/store/images/wordpress/uploads/2011/05/petting-kitty.jpg http://www.doggiestylish.com/store/images/wordpress/uploads/... Cats are awesome!
- saturn 15y ago
  But you still keep the cat, huh? That must be the parasite at work. Actually, now I have a whole new perspective on cat owners in general, and why they put up with their pets..
- arethuza 15y ago
  "Cats make you crazy by pawing your face all night for attention" For a while one of our cats was waking me up by climbing to the top of a wardrobe and then launching itself onto my stomach as I slept from this considerable height - which appears to be the cat equivalent of BASE jumping. The fact that I endured this behaviour a few times with relative good humour probably indicates that I probably have this mind control parasite!
kruhft 15y ago
My cat is so self reliant I love any attention he gives me. But then again, I raised him. But, WTF, cat stories on Hacker News? I don't know what to say!
- GuiA 15y ago
  Maybe you should read the linked article before commenting on it- it goes well beyond just cats ;)
giardini 15y ago
So what's the treatment for toxoplasmosis infection? Can I buy something OTC?
- Firebrand 15y ago
  No OTCs, but Minocycline looks promising, and it's cheap. http://www.ncbi.nlm.nih.gov/m/pubmed/1885421 http://www.ncbi.nlm.nih.gov/m/pubmed/1885421 Also, Maralone or something similar that uses atovaquone and proguanil.
rzbn 15y ago
So this is how it begins. A long and very informative article with no pictures. Next thing HN is filled with cat pictures.
winter_blue 15y ago
I'm glad he was smart/sane enough to even think about going to the lab. When something is messing with your mind, can you even think of such logical reasonable things?
- marshray 15y ago
  You've never heard of a mad scientist? You know "Mwahaahahaaa..." and all that. I'm surprised, it's a total cultural meme. Probably dates back to Newton and those other alchemists who were really fascinated by the, um, transformative properties of mercury.
  - ahoyhere 15y ago
    Seriously, OC probably means this: When you're having seemingly psychological affects/things that are just "part of who you are," it's almost impossible to begin to think that it might be some outside force. I used to take a medicine which I thought was fine; in the mean time, I developed worse and worse depression, anxiety, and all the time I thought it was a reasonable reaction to stuff in my life. THEN I got paranoid and thought my best friend and boyfriend were out to get me. Finally, something snapped. Finally, I thought, "whoa, this is not me." Turns out it was ALL the medicine. Yes, I had reasons to be depressed, but that's just not my type. Ended the medicine, ended all the side effects. It only took 3 years and a CRAZY extent of the side effects for me to realize it "wasn't me."
danso 15y ago
I love that the scientist at the heart of this story looks like a young Doc Brown
mazsa 15y ago
"We evaluated 148 case patients with recent T. gondii infection and 413 control patients. In multivariate analysis, an elevated risk of recent T. gondii infection was associated with the following factors: eating raw ground beef (adjusted odds ratio [aOR], 6.67; 95% confidence limits [CLs], 2.09, 21.24; attributable risk [AR], 7%); eating rare lamb (aOR, 8.39; 95% CLs, 3.68, 19.16; AR, 20%); eating locally produced cured, dried, or smoked meat (aOR, 1.97; 95% CLs, 1.18, 3.28; AR, 22%); working with meat (aOR, 3.15; 95% CLs, 1.09, 9.10; AR, 5%); drinking unpasteurized goat’s milk (aOR, 5.09; 95% CLs, 1.45, 17.80; AR, 4%); and having 3 or more kittens (aOR, 27.89; 95% CLs, 5.72, 135.86; AR, 10%). Eating raw oysters, clams, or mussels (aOR, 2.22; 95% CLs, 1.07, 4.61; AR, 16%) was significant in a separate model among persons asked this question. Subgroup results are also provided for women and for pregnant women. Conclusions. In the United States, exposure to certain raw or undercooked foods and exposure to kittens are risk factors for T. gondii infection. Knowledge of these risk factors will help to target prevention efforts." http://cid.oxfordjournals.org/content/49/6/878.full http://cid.oxfordjournals.org/content/49/6/878.full
nekojima 15y ago
We have six cats at the house here, hence the username 'nekojima', Japanese for 'cat island'. I have long suspected a parasitic role (either us or them for attention rather than brain damaging) or an element of craziness in our having so many cats. So far our own scientific analysis has been interrupted by near constant feline requests for attention, food or having to clean a little more than 'normal'.
- iopuy 15y ago
  ...'nekojima', Japanese for 'cat island'. Off topic but interesting. Guess "Iwo Jima" follows suit. I learn something new here every day.
  - tomflack 15y ago
    Yep, Sulfur Island. (http://jisho.org/kanji/details/%E7%A1%AB%E9%BB%84%E5%B3%B6 http://jisho.org/kanji/details/%E7%A1%AB%E9%BB%84%E5%B3%B6)
- white_devil 15y ago
  > hence the username 'nekojima', Japanese for 'cat island'. It's actually 'shima' for island. Not sure if 'jima' works too, but shima is definitely more common.
  - Someone 15y ago
    Iwo Jima, according to Wikipedia, is "Sulphur Island", so I would guess that either Iwo or Jima is OK, too.
  - alttag 15y ago
    The 'ji' (じ) uses the same kana as 'shi'　(し), just with some tick marks. Which sound is used in a compound word depends on the previous syllable. So, by itself, yes, it's "shima", but in a compound it could be either.
  - dschaab 15y ago
    (insert obligatory off-topic warning here) > It's actually 'shima' for island. Not sure if 'jima' works too, but shima is definitely more common. Correct, "island" is shima, but in this case we have a phenomenon in Japanese known as "sequential voicing" (連濁, rendaku) in which the first syllable of the second word of a compound is changed from an unvoiced consonant to a voiced consonant. This is particularly common when dealing with native Japanese compounds; i.e., compounds using words not derived from the imported Chinese pronunciations of characters. So "island" (島) by itself would be shima, but when used as a suffix, the initial consonant sh becomes voiced to j, and thus jima. Another example is "fire" (火), pronounced hi alone, but voiced to bi as the second half of words such as "fireworks" (花火, hanabi).
jakeonthemove 15y ago
I can't believe I read through the whole thing - it started off kind of crazy. Still, just as Flegr himself says, the change in behavior is minimal - chances are high that the average individual's life wouldn't be much different whether he/she had the parasite or not. Still, it's amazing how such a primitive organism can change your brain's function - makes you wonder if there's a parasite that's making people stupid/smart/lazy/etc.
- marshray 15y ago
  Perhaps even consciousness itself is... no. Host. Must. Not. Think. Such. Thoughts.
  - JoachimSchipper 15y ago
    Dennet ("Consciousness explained") does suggest that important parts of what we call "consciousness" are cultural, rather than inborn...
    - simon_weber 15y ago
      Blackmore in her introductions to consciousness suggests something related: that consciousness is an a concept (or illusion, to her) only widely known because it became a social meme.
gojomo 15y ago
How can they call it a parasite? It's clearly a commensal symbiote: for cats, it assists them in catching prey. In rats and humans, its changing prevalance helps adjust the relative expression of different behavioral strategies, faster than inheritance alone could. For example, the risk-taking and increased libido in rats shifts the infected slightly along the K-strategy/r-strategy reproductive spectrum. In some environments that's a win, others a loss, but the T.gondii increases rat behavior diversity, and thus the species' adaptability. Similarly, its modulating effects on human suspicion, gregariousness, investment in fitness-signalling (clothing), and obedience/trust sometimes help and sometimes hurt, depending on an ever-changing environment. What if we 'cured' this and found the resulting human populations were less resilient against war, ecological stresses, and rapid technological/cultural change? (I'm only half joking. And a meta-parasite is making me write apologetics for other parasites. And this entire comment is just a long way of saying "I, for one, welcome our new Toxoplasmosis gondii overlords" without getting immediately downvoted.)
- deleted 15y ago
  [deleted]
- liber8 15y ago
  Semantics point/question: The T. gondii, as viewed from the cat's perspective might be a symbiote, but from the rat's perspective, is certainly a parasite, isn't it? The T. gondii is benefiting at the expense of the rat. Do biologists classify things as both simbiotes and parasites?
  - gojomo 15y ago
    I think some rats also benefit: their adventurousness and increased sexual activity isn't always penalized with death, and even when it is, female rats prefer the infected male rats. So even if they live fast and die young, they may leave more offspring. Whether this is a net benefit at any one time probably depends on lots of things, and especially relative rat/predator populations. Just as human reproductive preferences seem to change in relation to wealth, population density, and life-expectancy. Regarding semantics, I do think something can be both a symbiote and parasite. When I first learned of 'symbiosis' it was in the context of mutually-beneficial relationships, but it seems the term can be more general. Wikipedia says scientists sometimes disagree whether 'symbiosis' should only be used to describe 'mutualist' relationships (where both benefit) or also 'parasitic' (one benefits and other is harmed) and 'commensal' (one benefits and other neither harmed nor helped) relationships. I should have used the word 'mutualist' in my above post, as that's what I was intending to imply. But the conjecture is intentionally fuzzy about whether the benefit is to the individual (it perhaps sometimes is) or the species (it perhaps always is, as long as both infection and non-infection are well-distributed).
Mitt 15y ago
Note how this linked article is from March 2012. And today is only February 10th :-)
- chanux 15y ago
  It's the early edition :)
- parfe 15y ago
  Print magazines date their online articles to match the print issue.
nodemaker 15y ago
When and if this research is sufficiently established, people will most likely have an averse (and perhaps unwarrantedly so) attitude to having cats as pets. Or maybe we will start vaccinating the kitties when they are young enough to start hunting.
- maxerickson 15y ago
  I guess it depends on how easy and effective treatments are. Pregnant women already routinely get advice not to clean litter boxes and such, which, anecdotally, sometimes translates into getting rid of the cat.
Mordor 15y ago
Really hoping alcohol is the cure...
zeroboy 15y ago
I have four cats and they are all indoors, so I guess I'm safe. But even if they weren't indoors, and I was vulnerable to this parasite, it wouldn't matter. I love them too much. The heart overrules the head in this matter.
- ars 15y ago
  > The heart overrules the head in this matter. I guess the parasite is working.
- Tichy 15y ago
  Could be the parasite talking... :-)
micheljansen 15y ago
After reading this article (which was very enjoyable by the way), I am now curious to find out if I myself may be the puppet of some parasite. Is there any way to find this out easily?
wisty 15y ago
> 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. This reminds me of a lot of cat-people I know. But that might just be selective recall.
peteretep 15y ago
> JAROSLAV FLEGR IS NO KOOK FUNNY HE SURE LOOKS LIKE ONE
nivertech 15y ago
I think T.gondi is the reason kitten videos are so popular on YouTube - CDC should look into this - it might be a global pandemic ;) I want to do an experiment: A/B testing landing page with and without cute kitten photos. I'm sure the one with cats photos will have much higher conversion rate.
- droctopu5 15y ago
  I also believe baby humans pass on a parasite that influences the parent to take and share voluminous photos and to regard every ounce of vomit from the child as a work of genius. This merits further study. Hold on, my cat is trying to type sometjfkd a;dsjkf jdfmfddddddsa fidddddddddddddddx fj
mb22 15y ago
Sigh - I spent over 2 hours talking with this reporter trying to help her understand the limitations of this guy's studies, but she doesn't seem to have taken on board anything I said... Of course, he could be right and it could also be that the X-rays emanating from a TV really do protect you from malaria. Or it could be that you watch TV indoors and so don't get as many mosquito bites. So, yes, it could be that Toxo causes increased risk-taking ... OR it could be that risk-takers drive their cars more crazily and do things that cause them to be slightly more likely to get infected! There can also be a strong socio-economic bias to infection rates and it could be that people from Czech farms are more likely to be infected from eating vegetables from their cat-feces-infested gardens and more likely to be in a car crash driving home wasted after a Polka 10 miles away in the nearest town in a Lada held together with superglue while their affluent city friends take the bus or drive a BMW and eat vegetables from a mass-production farm in the Ukraine. Etc., etc. On the other hand, the animal data are real (good, controlled experiments) and so it is TEMPTING to believe but the human data are really not good experiments. WAY too many "confounding variables" and no controls. There is one study with US military recruits that found a very slight increase in the likelihood that if you entered the army Toxo-negative and became Toxo-positive while in the army you were ever so slightly to be discharged with a diagnosis of schizophrenia than someone who stayed Toxo-negative. But the difference was not statistically significant, in my opinion (predict 13 patients would be discharged with schizophrenia in the Toxo-positive group and saw 15 were - NOT a significant difference). Bottom line, it's crap science and of course he could be right but so could the guy who says the world will end this November...
- MSexton 15y ago
  I had a hard time reading this and extracting "the limitations of this guy's studies", do you have any more details?
- ahoyhere 15y ago
  If one of the main risk factors for the parasite is exposure to cats, how exactly is that increased by "risk-taking behavior"? Are cats considered risky? You wrote a lot but none of it was persuasive. Other than random exaggerated "possibilities," what reason do you have to say it's crap science?
maeon3 15y ago
Ive dated 2 girls with cats, both of them turned out to be very crazy. Cats are a deal breaker for me. Crazy cat lady isn't the exception, its the rule. The ladies will argue about this to no end, don't waste your time, they are crazy. I wish I could send this note back to myself 18 years ago.
- adriand 15y ago
  I was tempted to mock your comment, but instead, out of a general wish for you to be happy even though I don't know you, I would really recommend that you expand the size of your study group. I'm sure if you think about it you can find some other similarities between these two women that may account for their issues. For example, both of them were apparently attracted to you...
  - maeon3 15y ago
    Excellent point! I have to try harder to not fall victim to the fallacy of post hoc.
evoltix 15y ago
The article is very interesting but seems to inflate the fact that if you have a cat you're most likely going to contract T. gondii. If indoor cats don't carry T. gondii and outdoor cats only carry the parasite for three weeks of their life, isn't the risk of getting this parasite very low since there is only a three week window? Perhaps I'm misinterpreting this. Please correct me if I'm wrong.

182 points by kawera 15y ago

Finally! A scientific explanation for http://www.youtube.com/watch_popup?v=sP4NMoJcFd4 http://www.youtube.com/watch_popup?v=sP4NMoJcFd4 !

kqr2 15y ago

For people with cats, some reassuring text: Given all the nasty science swirling around this parasite, is it time for cat lovers to switch their allegiance to other animals? Even Flegr would advise against that. Indoor cats pose no threat, he says, because they don’t carry the parasite. As for outdoor cats, they shed the parasite for only three weeks of their life, typically when they’re young and have just begun hunting.

draggnar 15y ago
hmm not so reassuring...
- batista 15y ago
  Are you kidding me? Besides the "Indoor cats pose no threat, he says, because they don’t carry the parasite", what other kind of reassurance you want? Not to mention the fact that people seem to live on fine with domestic cats for the last 2,000 years, with no casualties...
  - jakeonthemove 15y ago
    It also kind of explains the pyramids... it wasn't aliens, it was cats! :-)
    - Rariel 15y ago
      I know humor is sort of frowned up on HN but that was hilarious.
      - tripzilch 15y ago
        Downvoted for enjoying yourself.
  - ben0x539 15y ago
    Of course the author says that! He has cats, he must be infected too! But seriously, the claim wasn't that the parasite immediately kills people but makes them more disposed towards self-destructive behavior. The fact that, 2000 years after people started living with cats, humanity yet survives isn't really absolute proof to the contrary.
    - goblin89 15y ago
      Well, article claims that people really have started living with cats (that is, keeping them as pets) since 18th century in France, which is also when schizophrenia started to spread. So yeah, just over a century later and by the looks of it humanity is lucky to still survive! Imagine how different life would have been now without that crazy infected folk who like dangerous driving and become obsessed with insane ideas. =) By the way, can anyone clarify—is there a way to detect toxoplasmosis even in latent form? It seems from Wikipedia article that blood tests can't provide reliable results here.
    - draggnar 15y ago
      Maybe we have evolved with the influence of cats, who are really in power. They use us to achieve their objectives (mining for gold for some reason maybe?). The toxins keep us under control. It makes so much sense!
  - draggnar 15y ago
    Because i have an outdoor cat! When it was a kitten it would go outside hunting. And it wants to kill me.

rsanchez1 15y ago

Looks like there is something to the "crazy cat lady" after all.

commieneko 15y ago
Except the supposed behavior alteration in women is increased social activity, attention to appearance, neatness, and aversion to the smell of cat urine.
- gojomo 15y ago
  Average alteration. Given the article's suggestion that some people react differently to infection (as in the schizophrenia/immune-system discussion, and not just by gender), plus the similarity of cat ladies' behavior with infected rats in some dimensions, a link between this parasite and the 'cat lady' archetype is not an outlandish conjecture.

ryan-allen 15y ago

There's more information on this parasite on Wikipedia: http://en.wikipedia.org/wiki/Toxoplasmosis http://en.wikipedia.org/wiki/Toxoplasmosis Other links on the 'net that I've found are reporting (without any citations) that the parasite can be detected with a blood test (according to wikipedia, not true) and that it cannot be treated (again, according to wikipedia, also not true). I've seen articles about this parasite pop up over at least the last 5 years. If it was a truly serious problem I'm sure there'd be more information about it. It smells a bit like FUD though. Can anyone else elaborate on this further?

Alex3917 15y ago
"If it was a truly serious problem I'm sure there'd be more information about it." That's not really how science/epistemology work.
Game_Ender 15y ago
WebMd [1] and some other places [2] talk about it like it's a bacteria that your immune system fights off then you are safe from for the rest of your life. They don't seem to talk about any long term effects, and focus on just the risk the acute symptoms can have. [1] http://www.webmd.com/food-recipes/food-poisoning/toxoplasmosis-test http://www.webmd.com/food-recipes/food-poisoning/toxoplasmos... [2] http://www.pamf.org/serology/clinicianguide.html http://www.pamf.org/serology/clinicianguide.html
yew 15y ago
Five years isn't all that much time as far as bio-med research is concerned. I would expect to start seeing definite results in maybe a few years. As for detection and treatment, the subject being discussed in the Wiki article is the effect of initial infection. The parasite sticks around in a latent form after being "fought off" and is being hypothesized to have additional long-term effects.
Read_the_Genes 15y ago
A search for Toxoplasmosis on G-scholar reveals that this parasite is in fact a problem for immune compromised patients and infants. Although I do not think WebMD is a reliable source, another comment here cites them to indicate that infections are usually cleared up by our immune system. This appears to be plausible, but because the parasite enters cells, and can hide in a latent phase, your immune system may be unable to clear the infection permanently. Because the parasite can halt the cell cycle, it may be able to hide indefinitely. I would not be concerned about a latent parasite, but its re-emergence may become a problem if your immune system becomes compromised. A correction to your statement that, according to wikipedia, the disease cannot be tested by blood sample. Wikipedia, in fact, stats that it can be tested by blood or other tissue, but only if the parasite is active (non-latent). Regarding its effect on behavior, the parasite seems to increase dopamine levels and possibly inhibit fear response. Since the increased dopamine is caused by an enzyme made by the parasite, this probably only occurs during a full scale infection. The inhibition of fear may occur while the parasite is inactive, if the parasite is able to enter cells in your amygdala. I do not see this inhibition of fear as long-lasting, except perhaps in extreme cases. One disclaimer, I grew up with a few cats, so I may have been, or am currently, infected. I cannot rule out that this parasite is manipulating me to write this comment. Now I'm off to find some cat pee. Can't get enough of that smell, mmmmmmmm..... More technical wiki article: https://en.wikipedia.org/wiki/Toxoplasma_gondii https://en.wikipedia.org/wiki/Toxoplasma_gondii

genbattle 15y ago

This is a repost of an earlier submission at http://news.ycombinator.com/item?id=3573447 http://news.ycombinator.com/item?id=3573447 (It was probably posted previously before that)

jlees 15y ago

Here's a thought. Helen Fisher's research categorises people into four dominant personality types based on levels of neurochemicals: http://socionist.blogspot.com/2009/04/helen-fishers-types-explorer-builder.html http://socionist.blogspot.com/2009/04/helen-fishers-types-ex... For dopamine, which according to the cat article is elevated in Toxo-infected humans, the associated personality type is "risk-taking, curious, creative, impulsive, optimistic and energetic". Plus the associated decrease in fear response in rats: who does that sound like? i.e. I wonder what percentage of entrepreneurs are Toxo infected?

abecedarius 15y ago
Your question reminds me of a word one of my programs coined: entrepreneuropsychology.
rflrob 15y ago
Here's the question, though: are the risk-taking humans risk-taking because they're infected, or are they infected because they're risk taking. Correlation, unfortunately, doesn't imply causation. The "fatal attraction to cat urine" studies are somewhat imperfect [1]. I'm friends with a student who's doing similar studies with mice but with better spatial discrimination . The consensus seems to be that while the fear response goes down, the idea that it's attractive to the rodents is more difficult to replicate. [1] Free at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1690701/?tool=pubmed http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1690701/?tool=pu...

clutchski 15y ago

I loved this talk on Toxo and its effects on freewill by the always incredible Robert Sapolsky. http://www.edge.org/3rd_culture/sapolsky09/sapolsky09_index.html http://www.edge.org/3rd_culture/sapolsky09/sapolsky09_index....

spacemanaki 15y ago

Radiolab delved into this a bit in their show "Parasites" from a while back. You can listen to the relevant segment under "The Scratch", although I recommend the whole thing, of course: http://www.radiolab.org/2009/sep/07/ http://www.radiolab.org/2009/sep/07/

sakura_k 15y ago

This dude knows nothing about cats and crazy. Cats make you crazy by pawing your face all night for attention and sleeping all day because they're tired from being awake until dawn.

zalew 15y ago
hahaha, word. What makes you crazy is that cat wants attention when you are busy or sleepy and wants you away when you want to pet it, screams and breaks stuff when it's hungry and scratches your furniture. and this http://www.doggiestylish.com/store/images/wordpress/uploads/2011/05/petting-kitty.jpg http://www.doggiestylish.com/store/images/wordpress/uploads/... Cats are awesome!
saturn 15y ago
But you still keep the cat, huh? That must be the parasite at work. Actually, now I have a whole new perspective on cat owners in general, and why they put up with their pets..
arethuza 15y ago
"Cats make you crazy by pawing your face all night for attention" For a while one of our cats was waking me up by climbing to the top of a wardrobe and then launching itself onto my stomach as I slept from this considerable height - which appears to be the cat equivalent of BASE jumping. The fact that I endured this behaviour a few times with relative good humour probably indicates that I probably have this mind control parasite!

kruhft 15y ago

My cat is so self reliant I love any attention he gives me. But then again, I raised him. But, WTF, cat stories on Hacker News? I don't know what to say!

GuiA 15y ago
Maybe you should read the linked article before commenting on it- it goes well beyond just cats ;)

giardini 15y ago

So what's the treatment for toxoplasmosis infection? Can I buy something OTC?

Firebrand 15y ago
No OTCs, but Minocycline looks promising, and it's cheap. http://www.ncbi.nlm.nih.gov/m/pubmed/1885421 http://www.ncbi.nlm.nih.gov/m/pubmed/1885421 Also, Maralone or something similar that uses atovaquone and proguanil.

rzbn 15y ago

So this is how it begins. A long and very informative article with no pictures. Next thing HN is filled with cat pictures.

winter_blue 15y ago

I'm glad he was smart/sane enough to even think about going to the lab. When something is messing with your mind, can you even think of such logical reasonable things?

marshray 15y ago
You've never heard of a mad scientist? You know "Mwahaahahaaa..." and all that. I'm surprised, it's a total cultural meme. Probably dates back to Newton and those other alchemists who were really fascinated by the, um, transformative properties of mercury.
- ahoyhere 15y ago
  Seriously, OC probably means this: When you're having seemingly psychological affects/things that are just "part of who you are," it's almost impossible to begin to think that it might be some outside force. I used to take a medicine which I thought was fine; in the mean time, I developed worse and worse depression, anxiety, and all the time I thought it was a reasonable reaction to stuff in my life. THEN I got paranoid and thought my best friend and boyfriend were out to get me. Finally, something snapped. Finally, I thought, "whoa, this is not me." Turns out it was ALL the medicine. Yes, I had reasons to be depressed, but that's just not my type. Ended the medicine, ended all the side effects. It only took 3 years and a CRAZY extent of the side effects for me to realize it "wasn't me."

danso 15y ago

I love that the scientist at the heart of this story looks like a young Doc Brown

mazsa 15y ago

"We evaluated 148 case patients with recent T. gondii infection and 413 control patients. In multivariate analysis, an elevated risk of recent T. gondii infection was associated with the following factors: eating raw ground beef (adjusted odds ratio [aOR], 6.67; 95% confidence limits [CLs], 2.09, 21.24; attributable risk [AR], 7%); eating rare lamb (aOR, 8.39; 95% CLs, 3.68, 19.16; AR, 20%); eating locally produced cured, dried, or smoked meat (aOR, 1.97; 95% CLs, 1.18, 3.28; AR, 22%); working with meat (aOR, 3.15; 95% CLs, 1.09, 9.10; AR, 5%); drinking unpasteurized goat’s milk (aOR, 5.09; 95% CLs, 1.45, 17.80; AR, 4%); and having 3 or more kittens (aOR, 27.89; 95% CLs, 5.72, 135.86; AR, 10%). Eating raw oysters, clams, or mussels (aOR, 2.22; 95% CLs, 1.07, 4.61; AR, 16%) was significant in a separate model among persons asked this question. Subgroup results are also provided for women and for pregnant women. Conclusions. In the United States, exposure to certain raw or undercooked foods and exposure to kittens are risk factors for T. gondii infection. Knowledge of these risk factors will help to target prevention efforts." http://cid.oxfordjournals.org/content/49/6/878.full http://cid.oxfordjournals.org/content/49/6/878.full

nekojima 15y ago

We have six cats at the house here, hence the username 'nekojima', Japanese for 'cat island'. I have long suspected a parasitic role (either us or them for attention rather than brain damaging) or an element of craziness in our having so many cats. So far our own scientific analysis has been interrupted by near constant feline requests for attention, food or having to clean a little more than 'normal'.

iopuy 15y ago
...'nekojima', Japanese for 'cat island'. Off topic but interesting. Guess "Iwo Jima" follows suit. I learn something new here every day.
- tomflack 15y ago
  Yep, Sulfur Island. (http://jisho.org/kanji/details/%E7%A1%AB%E9%BB%84%E5%B3%B6 http://jisho.org/kanji/details/%E7%A1%AB%E9%BB%84%E5%B3%B6)
white_devil 15y ago
> hence the username 'nekojima', Japanese for 'cat island'. It's actually 'shima' for island. Not sure if 'jima' works too, but shima is definitely more common.
- Someone 15y ago
  Iwo Jima, according to Wikipedia, is "Sulphur Island", so I would guess that either Iwo or Jima is OK, too.
- alttag 15y ago
  The 'ji' (じ) uses the same kana as 'shi'　(し), just with some tick marks. Which sound is used in a compound word depends on the previous syllable. So, by itself, yes, it's "shima", but in a compound it could be either.
- dschaab 15y ago
  (insert obligatory off-topic warning here) > It's actually 'shima' for island. Not sure if 'jima' works too, but shima is definitely more common. Correct, "island" is shima, but in this case we have a phenomenon in Japanese known as "sequential voicing" (連濁, rendaku) in which the first syllable of the second word of a compound is changed from an unvoiced consonant to a voiced consonant. This is particularly common when dealing with native Japanese compounds; i.e., compounds using words not derived from the imported Chinese pronunciations of characters. So "island" (島) by itself would be shima, but when used as a suffix, the initial consonant sh becomes voiced to j, and thus jima. Another example is "fire" (火), pronounced hi alone, but voiced to bi as the second half of words such as "fireworks" (花火, hanabi).

jakeonthemove 15y ago

I can't believe I read through the whole thing - it started off kind of crazy. Still, just as Flegr himself says, the change in behavior is minimal - chances are high that the average individual's life wouldn't be much different whether he/she had the parasite or not. Still, it's amazing how such a primitive organism can change your brain's function - makes you wonder if there's a parasite that's making people stupid/smart/lazy/etc.

marshray 15y ago
Perhaps even consciousness itself is... no. Host. Must. Not. Think. Such. Thoughts.
- JoachimSchipper 15y ago
  Dennet ("Consciousness explained") does suggest that important parts of what we call "consciousness" are cultural, rather than inborn...
  - simon_weber 15y ago
    Blackmore in her introductions to consciousness suggests something related: that consciousness is an a concept (or illusion, to her) only widely known because it became a social meme.

gojomo 15y ago

How can they call it a parasite? It's clearly a commensal symbiote: for cats, it assists them in catching prey. In rats and humans, its changing prevalance helps adjust the relative expression of different behavioral strategies, faster than inheritance alone could. For example, the risk-taking and increased libido in rats shifts the infected slightly along the K-strategy/r-strategy reproductive spectrum. In some environments that's a win, others a loss, but the T.gondii increases rat behavior diversity, and thus the species' adaptability. Similarly, its modulating effects on human suspicion, gregariousness, investment in fitness-signalling (clothing), and obedience/trust sometimes help and sometimes hurt, depending on an ever-changing environment. What if we 'cured' this and found the resulting human populations were less resilient against war, ecological stresses, and rapid technological/cultural change? (I'm only half joking. And a meta-parasite is making me write apologetics for other parasites. And this entire comment is just a long way of saying "I, for one, welcome our new Toxoplasmosis gondii overlords" without getting immediately downvoted.)

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liber8 15y ago
Semantics point/question: The T. gondii, as viewed from the cat's perspective might be a symbiote, but from the rat's perspective, is certainly a parasite, isn't it? The T. gondii is benefiting at the expense of the rat. Do biologists classify things as both simbiotes and parasites?
- gojomo 15y ago
  I think some rats also benefit: their adventurousness and increased sexual activity isn't always penalized with death, and even when it is, female rats prefer the infected male rats. So even if they live fast and die young, they may leave more offspring. Whether this is a net benefit at any one time probably depends on lots of things, and especially relative rat/predator populations. Just as human reproductive preferences seem to change in relation to wealth, population density, and life-expectancy. Regarding semantics, I do think something can be both a symbiote and parasite. When I first learned of 'symbiosis' it was in the context of mutually-beneficial relationships, but it seems the term can be more general. Wikipedia says scientists sometimes disagree whether 'symbiosis' should only be used to describe 'mutualist' relationships (where both benefit) or also 'parasitic' (one benefits and other is harmed) and 'commensal' (one benefits and other neither harmed nor helped) relationships. I should have used the word 'mutualist' in my above post, as that's what I was intending to imply. But the conjecture is intentionally fuzzy about whether the benefit is to the individual (it perhaps sometimes is) or the species (it perhaps always is, as long as both infection and non-infection are well-distributed).

Mitt 15y ago

Note how this linked article is from March 2012. And today is only February 10th :-)

chanux 15y ago
It's the early edition :)
parfe 15y ago
Print magazines date their online articles to match the print issue.

nodemaker 15y ago

When and if this research is sufficiently established, people will most likely have an averse (and perhaps unwarrantedly so) attitude to having cats as pets. Or maybe we will start vaccinating the kitties when they are young enough to start hunting.

maxerickson 15y ago
I guess it depends on how easy and effective treatments are. Pregnant women already routinely get advice not to clean litter boxes and such, which, anecdotally, sometimes translates into getting rid of the cat.

Mordor 15y ago

Really hoping alcohol is the cure...

zeroboy 15y ago

I have four cats and they are all indoors, so I guess I'm safe. But even if they weren't indoors, and I was vulnerable to this parasite, it wouldn't matter. I love them too much. The heart overrules the head in this matter.

ars 15y ago
> The heart overrules the head in this matter. I guess the parasite is working.
Tichy 15y ago
Could be the parasite talking... :-)

micheljansen 15y ago

After reading this article (which was very enjoyable by the way), I am now curious to find out if I myself may be the puppet of some parasite. Is there any way to find this out easily?

wisty 15y ago

> 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. This reminds me of a lot of cat-people I know. But that might just be selective recall.

peteretep 15y ago

> JAROSLAV FLEGR IS NO KOOK FUNNY HE SURE LOOKS LIKE ONE

nivertech 15y ago

I think T.gondi is the reason kitten videos are so popular on YouTube - CDC should look into this - it might be a global pandemic ;) I want to do an experiment: A/B testing landing page with and without cute kitten photos. I'm sure the one with cats photos will have much higher conversion rate.

droctopu5 15y ago
I also believe baby humans pass on a parasite that influences the parent to take and share voluminous photos and to regard every ounce of vomit from the child as a work of genius. This merits further study. Hold on, my cat is trying to type sometjfkd a;dsjkf jdfmfddddddsa fidddddddddddddddx fj

mb22 15y ago

Sigh - I spent over 2 hours talking with this reporter trying to help her understand the limitations of this guy's studies, but she doesn't seem to have taken on board anything I said... Of course, he could be right and it could also be that the X-rays emanating from a TV really do protect you from malaria. Or it could be that you watch TV indoors and so don't get as many mosquito bites. So, yes, it could be that Toxo causes increased risk-taking ... OR it could be that risk-takers drive their cars more crazily and do things that cause them to be slightly more likely to get infected! There can also be a strong socio-economic bias to infection rates and it could be that people from Czech farms are more likely to be infected from eating vegetables from their cat-feces-infested gardens and more likely to be in a car crash driving home wasted after a Polka 10 miles away in the nearest town in a Lada held together with superglue while their affluent city friends take the bus or drive a BMW and eat vegetables from a mass-production farm in the Ukraine. Etc., etc. On the other hand, the animal data are real (good, controlled experiments) and so it is TEMPTING to believe but the human data are really not good experiments. WAY too many "confounding variables" and no controls. There is one study with US military recruits that found a very slight increase in the likelihood that if you entered the army Toxo-negative and became Toxo-positive while in the army you were ever so slightly to be discharged with a diagnosis of schizophrenia than someone who stayed Toxo-negative. But the difference was not statistically significant, in my opinion (predict 13 patients would be discharged with schizophrenia in the Toxo-positive group and saw 15 were - NOT a significant difference). Bottom line, it's crap science and of course he could be right but so could the guy who says the world will end this November...

MSexton 15y ago
I had a hard time reading this and extracting "the limitations of this guy's studies", do you have any more details?
ahoyhere 15y ago
If one of the main risk factors for the parasite is exposure to cats, how exactly is that increased by "risk-taking behavior"? Are cats considered risky? You wrote a lot but none of it was persuasive. Other than random exaggerated "possibilities," what reason do you have to say it's crap science?

maeon3 15y ago

Ive dated 2 girls with cats, both of them turned out to be very crazy. Cats are a deal breaker for me. Crazy cat lady isn't the exception, its the rule. The ladies will argue about this to no end, don't waste your time, they are crazy. I wish I could send this note back to myself 18 years ago.

adriand 15y ago
I was tempted to mock your comment, but instead, out of a general wish for you to be happy even though I don't know you, I would really recommend that you expand the size of your study group. I'm sure if you think about it you can find some other similarities between these two women that may account for their issues. For example, both of them were apparently attracted to you...
- maeon3 15y ago
  Excellent point! I have to try harder to not fall victim to the fallacy of post hoc.

evoltix 15y ago

The article is very interesting but seems to inflate the fact that if you have a cat you're most likely going to contract T. gondii. If indoor cats don't carry T. gondii and outdoor cats only carry the parasite for three weeks of their life, isn't the risk of getting this parasite very low since there is only a three week window? Perhaps I'm misinterpreting this. Please correct me if I'm wrong.