Cat Parasite May Increase Risk of Suicide In Humans 252
An anonymous reader writes "Researchers at the University of Maryland analyzing meticulous data collected by Danish authorities have identified a positive correlation between suicides among women with infection with the fairly common parasite T. gondii. Carriers were 53 percent more likely to commit suicide in a sample of 45,000 Danish women monitored for over a decade (researchers believe that the same correlation likely exists for men). Increased susceptibility to schizophrenia and bipolar disorder was also discovered. The physiological mechanism has not been determined, although some speculation centers around changes to dopamine levels. Two intriguing aspects were noted: 1) human infection often (but not always) begins by exposure to cats carrying the parasite, for example, by changing an infected animal's litter; and 2) the parasite spreads itself by infecting the nervous system of rodents, causing them to become suicidally attracted to feline odors which will increase the likelihood of their hosts being eaten by cats, whose digestive tracts provide the preferred environment for parasite reproduction."
So cats contract it by eating rodents... (Score:5, Funny)
...but it's still okay to eat cats, right? I mean, as long as you avoid the digestive organs?
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Re:So cats contract it by eating rodents... (Score:5, Funny)
...but it's still okay to eat cats, right?
The article is about human infections, so you might want to avoid eating humans. If you get infected, it will lower the dopamine level in your brain, and then you will get hungry for . . . another human brain . . .
. . . I think I just figured out how the Zombie Apocalypse thing will start . . .
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I think I just figured out how the Zombie Apocalypse thing will start . . .
will?
Re:So cats contract it by eating rodents... (Score:4, Funny)
Alf, is that you?
Re:So cats contract it by eating rodents... (Score:4, Insightful)
Wash your hands.
If you are a cat owner, and you can't handle the simple fact that you are dealing with feces and vomit every day without a proper hygiene protocol, something has already gone wrong.
Re:So cats contract it by eating rodents... (Score:5, Funny)
Wash your hands.
If you are a cat owner, and you can't handle the simple fact that you are dealing with feces and vomit every day without a proper hygiene protocol, something has already gone wrong.
I've got cats and I don't handle their feces every day. I let my neighbourds do that when the cats go and crap in their rosebeds.
Re:So cats contract it by eating rodents... (Score:5, Funny)
...but it's still okay to eat cats, right?
I have actually eaten cat. Many years ago, I was in the red light district of Panama City (Fourth of July Street) with some fellow jarheads, and some guy had a "monkey" roasting on a spit. So we each bought a slice. We were eating as we walked along, and I noticed a young woman laughing at us. I asked her what was so funny.
She smiled asked "Do you know what you are eating?"
"Monkey meat."
"Nope. It's an alley cat."
Anyway, it tasted like chicken.
In Dutch it is called "dakhaas" (Score:3)
Dakhaas literally means roofrabbit and refers to the fact that if you cut the legs, you can pass cat for rabbit. Not in practice anymore but we did have the hungerwinter here thanks to the Americans being to scared to advance and leave the British and Polish forces without backup.
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Coincidentally, in German it's called "Dachhase" and the origin is probably the siege of Vienna by the Turks in 1683, so I guess you got the term from the Germans.
The chicken and egg problem all over again (Score:5, Interesting)
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Either way this explains Caturday.
Re:The chicken and egg problem all over again (Score:5, Interesting)
Do the crazy cat ladies have cats because they are crazy, or are they crazy because they have cats?
The parasite also causes decreased sexual inhibition. Translation: It makes women sluttier. No corresponding effect was found in men. Of course, this effect isn't as widely documented for obvious political reasons...
Re:The chicken and egg problem all over again (Score:5, Funny)
Do the crazy cat ladies have cats because they are crazy, or are they crazy because they have cats?
The parasite also causes decreased sexual inhibition. Translation: It makes women sluttier. No corresponding effect was found in men. Of course, this effect isn't as widely documented for obvious political reasons...
That is because in men there is no sexual inhibition to effect.
Re:The chicken and egg problem all over again (Score:5, Funny)
Sure there is. It's just that rather than being controlled by the brain, it's governed by an external organ known variously as a "wife," "girlfriend," or, in the case of Slashdotters, "mother."
Re:The chicken and egg problem all over again (Score:5, Funny)
Q: What do Slashdotters use for birth control?
A: Their mothers!
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How did you manage to read misogyny in parent's post? Do you consider having no sexual inhibitions to be a positive thing?
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The two things that make people crazy are sex and money. Start talking about either and stand back and watch the goofy unfurl./p?
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Guilt about sex is one of the things religion uses to keep people in line.
Except for the whole book of Song of Solomon, you mean.
But dont let your ignorance get in the way of your anti-religious sentiment, this is slashdot and theres karma to be had.
Re:The chicken and egg problem all over again (Score:5, Funny)
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Guilt about sex is one of the things religion uses to keep people in line. Reduce guilt about sex and you reduce religion's hold over the populace. We can't have that happening, now can we?
Depends: do you consider the future portrayed by Brave New World good or bad?
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Depends: do you consider the future portrayed by Brave New World good or bad?
about 12% good, with some bad, also a modicum of mediocre, a little 'could do better' and a dash of awful.
Life is a little more complicated than you're giving me options for...
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Yes.
Re:The chicken and egg problem all over again (Score:5, Informative)
If you knew anything about these parasites, you would not write what you just did.
Cats are carriers. Rodents are part of their life cycle. Rodents infected with these parasites tend to be "more brave", some even to the point of taunting a cat to attack them. The cat eats infected rodents, and the cycle of the parasite is complete as it returns to the soil and rodents pick it up once more.
Humans are just unintended side show for the parasite, but since these affect behaviour in mice brains, it is not surprising these parasites affect human brains too.
http://www.livescience.com/5631-zombie-ants-controlled-fungus.html [livescience.com]
Is another example of similar effects in non-mammals by other, yet similarly acting organisms.
In a similar unrelated note, there are experiments that show even more bizarre behaviours, like effectively a "personality transplant" by a swap of gut bacteria cultures between two mice. One aggressive and another docile. Swap their gut cultures, and you swap their bahaviours!
There is plenty of other research starting to appear in this area,
http://www.sciencedaily.com/releases/2011/05/110517110315.htm [sciencedaily.com]
So basically, how you eat may tell what you are/may become and your becteria and viruses play bigger part in your life than you can image.
Increased rate in traffic accidents (Score:5, Interesting)
You seem to know about this field. Can you translate this part for me?
Separate logistic regression for RhD-negative subjects showed a 2.53 times higher risk of traffic accidents in Toxoplasma-infected than Toxoplasma-free subjects (CI95: 1.12–5.7, t = 2.23, P = 0.026). http://www.biomedcentral.com/1471-2334/9/72 [biomedcentral.com]
Are they really saying that this is causing "2.53 times higher risk of traffic accidents" among their infected population of Czech male military draftees???
Imagine the repercussions if this is found to be also true in other populations (not that it will be, and not that correlation equals causation, but...):
Car Insurance rates (or driver licenses) could start depending on the results of those blood tests. Criminal sentencing could be affected by the results of those tests. And at the very minimum, the next time you'd fill out a questionnaire for getting car insurance, or filling out an application for becoming a truck driver or operating heavy machinery, or applying to get into the military, you'd be asked all kinds of questions about your history with cats (whether you owned one, your significant other owned one, or whether your family ever owned one while you were growing up).
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Re:The chicken and egg problem all over again (Score:4, Funny)
"Do the crazy cat ladies have cats because they are crazy, or are they crazy because they have cats?"
Yes.
Obligatory (Score:4)
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First off, the study only knew about diagnosed mental illnesses. Second off, what effect does economics have on this? What about things like iv drug use or nssi, things that can infect a person and are generally associated with a higher risk of suicide later on? I'm also doubting that those 2 things would show up on a persons medical record unless they where severe enough to require treatment.
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what the fuck are you talking about? no statistic in and of itself indicates a "cause and effect" relationship. they indicate correlations only, which of course are sometimes suggestive.
and why do you need RR > 3? what if there is a real cause and effect relationship which only increases the relative risk by 1.8? does it just never get published until, by freak chance, the sample happens to give an RR above 2? why don't you use p-value to determine existence of a relationship, and then, if significant, i
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before someone points it out, yes "increases the relative risk by 1.8" is totally wrong. i meant, "has an observed relative risk of 1.8."
there are several well-established causal links with low RR. for example, very moderate alcohol consumption on oral cancer; the RR is ~1.5, but the p-value is near 0, and consuming more alcohol increases the RR. it's pretty convincing, but by your rule i guess since moderate alcohol consumption has RR below 2, alcohol doesn't have a causal effect until you have ~4 drinks a
chicken or the egg? (Score:2)
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Maybe the lady got one cat, got infected, went crazy, and got 19 more? (Remember, the parasite causes rodents to be attracted to cats; maybe it has a similar effect in humans.)
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Humans don't need parasites to be attracted to cats. Kittens work for that purpose just fine.
Cat have already "hacked" our instincts. (Score:3)
How can you be certain they work via a mechanism other than the parasite?
Take a few random specimen of the felidae family.
For each specimen, compare the young baby with the adult.
- lion cub and adult lion
- kitten and adult house cat
etc.
Notice anything peculiar? Unlike the wilder specimen, house cats tend to retain much more juvenile caracteristics: bigger eyes, more fluffy. (And that works also for noise: most bigger cats tend to be silent, or occasionnaly express deep menacing roars. Only house cats (even more than alley cats) tend to meow a lot, and keep a rather high-pitched
don't trust em (Score:5, Funny)
sure, this looks like valid research, until you see the citations
Resurch dun by Carnegie Meloncat Institute fellows:
Hovercat
Longcat
Dunecat
with speshul thx 2 cieling cat hoo make all tings possible
Kill all cats. (Score:5, Insightful)
That's what people would say if cats were ugly, anyway. But they are cute, so they are permitted to carry disease. Only ugly species are eligable for culling.
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Well, they also help defend against the Plague by killing the carriers.
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It has been my experience that without exception people that think of cats that way tend to be serial killers or have the potential to be serial killers anyway.
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They are a menace to public health. That's what people would say if cats were ugly, anyway. But they are cute, so they are permitted to carry disease. Only ugly species are eligable for culling.
All animals carry diseases, including human beings. Maybe we should sterilise the Earth, and leave a nice clean Lunar environment.
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Nuke it from orbit.
It's the only way to be sure.
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And how many have you seen before they popped out? I know I tried looking but no matter how much I stretched my wife I just couldn't see them...
Didn't you go to any of your wife's ultrasounds during her pregnancy?
Or do you live in the USA or other country with 3rd world medical care?
The Origin? (Score:5, Funny)
Let's tease the tiger (Score:3)
The purpose of the behavioral change in rats is to get the rat gobbled up by a cat so that the parasite could reproduce. I wonder if toxoplasmosis in humans promotes reckless and suicidal behavior. This would give the parasite another opportunity to reproduce. Just imagine 50,000 years ago a suicidal or reckless person decided to taunt a hungry tiger. One strike by the annoyed tiger, and the toxoplasmosis would have access to a warm cat gut to reproduce. Isn't nature wonderful
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I have 7 cats (Score:2)
and no one has offed themselves in my house. Maybe smoking dope counteracts the parasite :)
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Zombie Virus (Score:5, Funny)
Once the cats perfect this virus it's all over...
Re:Zombie Virus (Score:5, Funny)
You mean "purr-fect" this virus, eh?
Liger Cat Box (Score:2)
They are no going to be the same (Score:2)
by changing an infected animal's litter
Now I know that they are not going to be the same between men and women. A woman is likely to change their litter box more than once a year; which is what a man will do.
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What I do is the cat lives outside. But as a gadget lover, what I would do if I had an indoor cat is get a snazzy litterbox. And if the cat crapped on the rug in protest of the shit machine I'd swap it out for another cat. Maybe show the new cat a picture of the old cat going away...
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There's a better way - toilet-train the furballs instead. I have two cats whom I, after much hair-pulling, successfully trained to use a regular toilet. It's also a lot cheaper and more sanitary, and stinks less too. One flush and their leavings are dealt with. No litter box to clean also means no more of a risk of diseases than one encounters from regularly cleaning a toilet used only by humans in the first place. Note that the smarter the cat and the more time and patience you can muster, the faster
Religion too (Score:3)
Also evidence of correlation with religion ; a higher incidence [nih.gov] than average amongst Muslims and Christians (a shame this study didn't assay Atheists though).
Scooped (Score:2)
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50% is still not that much (Score:4, Interesting)
What I see out of this, and others like it, is that there are a large number of diseases we get infected with over our lives that never leave us, and have effects well into our old age. We wouldn't have "evolved" out of them because the evolutionary pressure for things that don't affect us until after we've passed on our genes is small and indirect. How many "diseases" and infections do we have by the time we are die? What would our old age be like if we managed to avoid/cure them all?
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It affects risk management, increasing risk-taking behaviour,
If true, what do you think would be appropriate steps to take? It seems to me to be more a dog-based conspiracy. Some mythical "cat-spread" disease that's incurable that causes unknown undesirable effects.
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A 50% increase is statistically significant
No, you don't know whether it's statistically significant unless you know the uncertainty in the measurement. A 50% increase with a standard deviation of 100% would not be statistically significant. A 1% increase with a standard deviation of .1% would be statistically significant. And that's all without considering sample size.
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A relatively simple method would be a feedback loop. The parasite could stimulate dopamine receptors whenever it is exposed to compounds linked to feline odor. Since the parasite is already in the nervous system, it would be pretty easy for it to be hanging around the blood-brain barrier or the nasal system to receive the odors first hand even.
Ever see the dumb shit people will do coked up? Now reduce the cognitive inhibitions to the level of a rodent. Chemically, it's all the same.
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I think it T. gondii attacks some regulatory function in the brain that inhibits risk-taking behavior, which for rodents is associated via different mechanisms with the detection of cats and other predators.
The rodents in question remain afraid of open spaces and unfamiliar foods. The only thing that appears to be targeted is the fear of cat urine.
My evidence differs... (Score:2)
Of course, my evidence consists of multiple repeated viewings of Tom and Jerry, Sylvester and Tweety, and Pinky and the Brain, but according to my research, it's exposure to Mince and Rats that creates suicidal tendencies in Cats.
Just saying.
Narf.
FUCKING CATS! KILL THEM ALL! (Score:2)
Shit i have 2 cats...
FUCK EM!
Interesting topic, poor summary (Score:5, Interesting)
The Danish study is just the latest in a long series of studies which demonstrate a correlation between toxoplasmosis seropositivity and psychiatric problems-- it's been linked to schizophrenia and ADHD, and so on. Wikipedia has a good article on the topic.
It's pretty interesting. Apparently something like 10% of the US population is seropositive for toxo. The infection is thought to be "contained" immunologically, but encysted organisms are still present in muscle and nervous tissue, and the process of "containment" may induce a subtle inflammatory state which affects a broad variety of neurotransmitters (not just dopamine). It's also possible that the causation works the other way-- the people who get chronic infections may have something about their immune system that is different to begin with, and the difference might predispose them to psychiatric problems independently of toxo infection. Good discussion of all that in the Danish study, which was published in Archives of General Psych and seems to be non-paywalled.
What will be really interesting is to see what happens if you identify psychiatric patients with chronic toxo and try to eradicate the toxo with antibiotics-- do their psych symptoms improve? There have been at least two studies I could find (one where it helped and one where it didn't), and apparently there's a large-scale study getting started in the UK.
Same parasite causes MISCARRIAGES during prenancy (Score:3)
Subj says it all. Others may have noticed the same.
Could those in the extra 53% suicidal women have suffered earlier miscarriages, by any chance?
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I also seem to remember that the same parasite can cause a whole host of problem in a developing fetus too.
Control group (Score:5, Interesting)
1) What if depressed people get cats, and that's why they have the parasite? Did they check people who have cats but aren't depressed?
It's probably not related to cats, because most people who get this parasite get it from undercooked meat.
2) What if depressed people are more susceptible to this parasite because they are depressed? What if non-depressed people are capable of fighting off the parasite with a stronger immune system?
There was no correlation between people who had the parasite, and people who had a history of mental illness. (Also, correlates with other studies, that might have had better control groups, I'm too lazy to check them out to see).
Cat Scratch Fever..... (Score:2)
It was popular in the 1970's, you can go to the doctor and get the cure.... ;-)
a better explanation of the study (Score:5, Informative)
http://www.nursingtimes.net/home/clinical-specialisms/infection-control/cat-ladies-suicide-risk-probed/5046843.article?blocktitle=Behind-the-Headlines&contentID=4530 [nursingtimes.net]
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Thanks, I was looking for that number. That's quite significant with 45k people.
Ceiling cat iz in ur head... (Score:2)
I've heard this before (Score:2)
I can't help thinking that I've heard this before some years ago. Am I right or is this really a new finding?
Terrorist Weapon? (Score:4, Funny)
(obligatory)
But what if terrorists find a way to use this?
Re:Terrorist Weapon? (Score:5, Funny)
Emo music sales soar 10.000%.
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In some countries, the period is used to separate 1000's and the comma is the "decimal" point. Thus, 10,000 dollars would be 10.000,00
Re:Terrorist Weapon? (Score:4, Informative)
Re:Terrorist Weapon? (Score:5, Funny)
As it should be. Now if we could start pushing the one true Imperial unit system. Keep the faith brothers.
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Well, given how slashdot explicitly declares itself an American centric site...
Re:Terrorist Weapon? (Score:5, Funny)
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Correlation != causation (Score:5, Interesting)
Suicidally? Being attracted to something known to shorten your lifespan doesn't mean you're suicidal. Take one example: Americans gorging themselves on McDonald's, then flooding hospitals with heart disease cases in an attempt to stay alive. If they were suicidal, they'd just keep eating more burgers and look emo about it till they died.
Re:Correlation != causation (Score:5, Funny)
Not to mention the fact that attraction to feline odors is only suicidal to humans when we run into burning buildings to try and retrieve our kitties from underneath the bed, and emerge with second-degree burns and major laceration wounds (burns from the fire, laceration wounds from... well, nevermind. Our little kitty is safe. Pissed, but he'll get over that as soon as we give him some tuna.)
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Take one example: Americans gorging themselves on McDonald's
Even Americans we know that there's more to life than McDonalds.
For example, there's Burger King, KFC, Taco Bell, Dunkin Donuts and all sorts of other places.
Re:Are they sure it's not just "women with cats" (Score:4, Funny)
Hey, I'm a crazy cat MAN, you insensitive chauvinist clod!
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And I'm a standard cat fanatic, you clod!
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There is no "Uninformative" to mod you down.
Yeah they've done plenty of studies linking various changes in human behavior to toxoplasmosis infection. Your claim is so strange that I almost wonder if you're part of the pro-toxoplasmosis conspiracy or maybe you're a toxoplasmosis forcing a crazy cat lady to type these things.
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No it's not. TFA states "positive correlation", that does not mean it has been proven, but just they are seeing an interesting trend.
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Re:A witch weighs the same as a duck (Score:4, Insightful)
Next time, please at least read the article before spreading your inanity. Scientists usually think of the simple stuff.
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I know what you're trying to say, but this is a contradiction in terms. There is no sun in Britain to give anyone a red neck.
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In addition to it being torture on the animal it will have all sorts of negative effects on humans, and this is just one of them. Having animals as "pets" essentially holding them prisoner. We have come to a point we no longer need animals for anything whether it is food, clothing, companionship, rescue, etc. Most countries now have a ban on having humans as slaves so why not have a ban on animals as slave as well?
Good luck trying to keep a cat prisoner.