Just who is the master? Kitty, toxoplasma gondii and you

The Something Awful Forums > Discussion > Debate & Discussion > Just who is the master? Kitty, toxoplasma gondii and you

Pegged Lamb: Nov 5, 2007; Can't post for 3 years!

I came across this disturbing article today about something I read about before http://www.theatlantic.com/magazine/archive/2012/03/how-your-cat-is-making-you-crazy/308873/?utm_source=FB1009_15

The premise is this: Cats, cows, pigs and rodents can pick up the infectious germ toxoplasma gondii from moist soil. They become hosts to colonies of the parasite which then secretes itself mainly in their feces. Here's where we come in

quote:

Humans, on the other hand, are exposed not only by coming into contact with litter boxes, but also, he found, by drinking water contaminated with cat feces, eating unwashed vegetables, or, especially in Europe, by consuming raw or undercooked meat. Hence the French, according to Flegr, with their love of steak prepared saignant�literally, �bleeding��can have infection rates as high as 55 percent. (Americans will be happy to hear that the parasite resides in far fewer of them, though a still substantial portion: 10 to 20 percent.)

This parasite, which is a single cell pathogen that can infect most of the animal and bird. After having done so, the parasite begins to reorder the brains connections in ways that make the carrier more reckless. For example, mice have been used as a vector for the infection of cats by being manipulated by the parasite into approaching cats, after being enticed by the lure of their scent by the virus.
http://www.nature.com/news/parasite-makes-mice-lose-fear-of-cats-permanently-1.13777

The apparent effects on humans are subtle but potentially very dangerous and very significant- and seem to vary by gender.

quote:

The subjects who tested positive for the parasite had significantly delayed reaction times. Flegr was especially surprised to learn, though, that the protozoan appeared to cause many sex-specific changes in personality. 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.

The findings were so bizarre that Flegr initially assumed his data must be flawed. So he tested other groups�civilian and military populations. Again, the same results. Then, in search of more corroborating evidence, he brought subjects in for further observation and a battery of tests, in which they were rated by someone ignorant of their infection status. To assess whether participants valued the opinions of others, the rater judged how well dressed they appeared to be. As a measure of gregariousness, participants were asked about the number of friends they�d interacted with over the past two weeks. To test whether they were prone to being suspicious, they were asked, among other things, to drink an unidentified liquid.

The results meshed well with the questionnaire findings. Compared with uninfected people of the same sex, infected men were more likely to wear rumpled old clothes; infected women tended to be more meticulously attired, many showing up for the study in expensive, designer-brand clothing. Infected men tended to have fewer friends, while infected women tended to have more. And when it came to downing the mystery fluid, reports Flegr, �the infected males were much more hesitant than uninfected men. They wanted to know why they had to do it. Would it harm them?� In contrast, the infected women were the most trusting of all subjects. �They just did what they were told,� he says.

Why men and women reacted so differently to the parasite still mystified him. After consulting the psychological literature, he started to suspect that heightened anxiety might be the common denominator underlying their responses. When under emotional strain, he read, women seek solace through social bonding and nurturing. In the lingo of psychologists, they�re inclined to �tend and befriend.� Anxious men, on the other hand, typically respond by withdrawing and becoming hostile or antisocial. Perhaps he was looking at flip sides of the same coin.

Closer inspection of Flegr�s reaction-time results revealed that infected subjects became less attentive and slowed down a minute or so into the test. This suggested to him that Toxoplasma might have an adverse impact on driving, where constant vigilance and fast reflexes are critical. He launched two major epidemiological studies in the Czech Republic, one of men and women in the general population and another of mostly male drivers in the military. Those who tested positive for the parasite, both studies showed, were about two and a half times as likely to be in a traffic accident as their uninfected peers.

Ok, so some of that conflicts with the archetype of the cat lady, but only by reversing the genders. This seems like a big deal. Then there is the schizophrenia angle. Apparently schizophrenic people who test positively for infection overwhelmingly have neo cortical shrinkage.

quote:

He hands me a recently published paper on the topic that he co-authored with colleagues at Charles University, including a psychiatrist named Jiri Horacek. Twelve of 44 schizophrenia patients who underwent MRI scans, the team found, had reduced gray matter in the brain�and the decrease occurred almost exclusively in those who tested positive for T. gondii.

quote:

A parasite that infects up to one-third of people around the world may have the ability to permanently alter a specific brain function in mice, according to a study published in PLoS ONE today1.

quote:

In humans, studies have linked Toxoplasma infection with behavioural changes and schizophrenia. One work found an increased risk of traffic accidents in people infected with the parasite2; another found changes in responses to cat odour3. People with schizophrenia are more likely than the general population to have been infected with Toxoplasma, and medications used to treat schizophrenia may work in part by inhibiting the pathogen's replication.

I'm not sure what to discuss here. It seems if that infection figure is accurate, and the personality changes which are associated with the parasite are permanent, then you have this invisible pandemic that could be a contributor to all sorts of social and public safety ills; but wouldn't this have been the case for many decades at least by now? Could other parasites be causing similar behavioral changes? I'm looking for insights from the biologically versed especially.

# ? Oct 10, 2014 21:31

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# ? Apr 23, 2024 16:50

IAMNOTADOCTOR: Sep 26, 2013

I've always really liked the idea behind this, and some of the science is reasonably solid, but i'm very sceptical about robustness of these correlations, especially with traffic accidents. Other papers found no correlation between the severity of infection and the concentration capabilities of patients. As it stands, it could very well still be a peculiar statistical artefact as there was no attempt made to correct for confounders such as socio economic status: poor people are more likely to be infected and possibly more likely to have a traffic accident.

# ? Oct 10, 2014 22:38

Freakazoid_: Jul 5, 2013; Buglord

I sometimes see this disease mentioned in some paranormal sites so my impression of it is largely skeptical. However this is the first time I've heard it affecting women and men differently.

# ? Oct 11, 2014 15:00

McAlister: Nov 3, 2002; by exmarx

I've always found it funny that toxoplasma supposedly causes ... In each gender ... stereotypical gendered behavior.

That just seems a little to pat to me. I mean, imagine if they were reporting it made gay people more fabulous or black people crave watermelon.

# ? Oct 11, 2014 15:37

Chard: Aug 24, 2010

Don't care OP fuzzy tummies need nuzzling more than I need my whole brain

# ? Oct 11, 2014 15:45

Zodium: Jun 19, 2004

I didn't read the paper because robust behavioral t. gondii findings in humans are about as likely as robust behavioral astrology or ESP findings, but the findings aren't really "bizarre" at all unless you have basically no knowledge of the scientific psychology literature. The results, as they are reported by The Atlantic, can either readily be explained in much less sensational terms of anxiety, without the need to introduce a magic bug that causes subtle and complex behavioral changes in humans for no apparent evolutionary reason, or simply fail to rule out such an explanation.

Anxiety can explain the personality and infection rate differences: it is known that anxious people are likely to be more introverted and more likely to adopt a preventive regulatory focus, and therefore more likely to perceive threat in situations such as the unknown fluid task; anxious people perform less well on vigilance tasks; though I'm not really up to date on the pet ownership literature, if such literature exists, I think it's very plausible that trait anxiety would predict pet ownership, and should have been controlled for before entertaining the idea of magic bugs. Did he even control for pet ownership? The neurodegeneration in schizophrenia cases is a little interesting, I guess, but it's incredibly dubious to jump from there to healthy brains.

In conclusion, there's basically no explanatory reason to introduce t. gondii here anywhere. It makes for a more complicated model without actually explaining anything that plain trait anxiety doesn't. t. gondii's behavioral effects on kitty's food sources, like mice, are well established and make reasonably good sense, whereas the published results on t. gondii behavioral effects in humans (that I've seen), including and especially this one, are invariably specious nonsense that never feature rigorous or even acceptable methodology.

Zodium fucked around with this message at 15:55 on Oct 11, 2014

# ? Oct 11, 2014 15:53

Dmitri-9: Nov 30, 2004; There's something really sexy about Scrooge McDuck. I love Uncle Scrooge.

The pathology should be considered before you start to worry abut stuff like this. France has an infection rate of 50% but it is a perfectly functioning country. Imagine if a country had a 50% prevalence for schistosomiasis or bacterial meningitis you wouldn't be able to say the same thing.

# ? Oct 11, 2014 16:17

Xibanya: Sep 17, 2012; Clever Betty

So since I have a cat I probably have a terrible brain parasite? Groovy.

# ? Oct 12, 2014 03:59

Polygynous: Dec 13, 2006; welp

Only if it's an outdoor cat and only certain times of year. At least I think I remember that from the last time this came up.

# ? Oct 12, 2014 04:09

Slaan: Mar 16, 2009; ASHERAH DEMANDS I FEAST, I VOTE FOR A FEAST OF FLESH

Chard posted:

Don't care OP fuzzy tummies need nuzzling more than I need my whole brain

Quoted for truth. Cattes are in need of hand-power more than brain-power, my friend the OP. :catdrugs:

# ? Oct 12, 2014 14:11

Fame Douglas: Nov 20, 2013; by Fluffdaddy

Xibanya posted:

So since I have a cat I probably have a terrible brain parasite? Groovy.

spoon0042 posted:

Only if it's an outdoor cat and only certain times of year. At least I think I remember that from the last time this came up.

Are cats even that important an infection vector, compared to other avenues like meat or unwashed fruits and vegetables? Or contaminated knives, cutting boards?

# ? Oct 12, 2014 15:28

Cabbages and Kings: Aug 25, 2004; Shall we be trotting home again?

I don't really think of it as a disease. It's just a condition that helps me like cats.

# ? Oct 12, 2014 16:20

Anime Schoolgirl: Nov 28, 2002

Tim Raines IRL posted:

I don't really think of it as a disease. It's just a condition that helps me like cats.

Cat brainworm conspiracy confirmed.

# ? Oct 12, 2014 16:59

Trochanter: Sep 14, 2007; It ain't no sin
to take off your skin, And dance around in your bones!

Dmitri-9 posted:

France has an infection rate of 50% but it is a perfectly functioning country.

I wouldn't say that

# ? Oct 14, 2014 18:22

Coldbird: Jul 17, 2001; be spiritless

IIRC the Wikipedia article on toxo stated that there wasn't even a correlation between infection and cat ownership, it had a lot more to do with eating uncooked meat, etc. The association with cats had to do with a scare in I think the 80s when pregnant women were told to avoid litter boxes.

# ? Oct 14, 2014 18:42

SBJ: Apr 10, 2009; Apple of My Eye

Laughter in the Sky

I hate cats and I don't dress like a slob so I think I'm in the clear

# ? Oct 22, 2014 10:35

Desiderata: May 25, 2005; Go placidly amid the noise and haste...

McAlister posted:

I've always found it funny that toxoplasma supposedly causes ... In each gender ... stereotypical gendered behavior.

That just seems a little to pat to me. I mean, imagine if they were reporting it made gay people more fabulous or black people crave watermelon.

While I wouldn�t want to make any claims about the validity of the actual causal hypothesis here. It isn�t necessarily sexist to assume that when exposed to something that causes people to feel anxious, that angst may express itself by a conscious effort to meet societal gender expectations. Not because of anything inherent to the biology of the genders, but because fear of social repercussions for standing out may be at the forefront of the anxious mind, and society makes those gender expectations painfully clear to us all. It�s still a social-construct, even if its knock on effects are showing up in a scientific setting.

So a drug causing a statistically significant divergence in �women do X, men do Y� can show up in an experimental setting, not because of some kind of gendered medical biotruth. But instead because the drug is putting people under a certain psychological pressure, and we have been taught by society all our lives to respond to that pressure though X or Y respectively. Societies problem thus becomes a scientific statistical aberration that people can read their own biases into.

Though you are right to question the validity of it in any case.

# ? Oct 22, 2014 11:33

im gay: Jul 20, 2013; by Lowtax

So um, how do I get this loving thing out of me.

# ? Oct 22, 2014 12:35

SBJ: Apr 10, 2009; Apple of My Eye

Laughter in the Sky

im gay posted:

So um, how do I get this loving thing out of me.

It's too late for you, enjoy your hobo fashion sense and schizophrenia-induced car accidents.

Unless you're a woman, in which case enjoy being hot, smart and personable I guess.

# ? Oct 22, 2014 14:34

MODS CURE JOKES: Nov 11, 2009; OFFICIAL SAS 90s REMEMBERER

poo poo, man. I feel like Cat Kobain over here, all grungy with my kitties. I ain't give a drat, got such a cute catte :3:

# ? Oct 22, 2014 14:43

OneEightHundred: Feb 28, 2008; Soon, we will be unstoppable!

im gay posted:

So um, how do I get this loving thing out of me.

Get a dog, obviously.

# ? Oct 22, 2014 15:08

Irony Be My Shield: Jul 29, 2012

It's interesting that this parasite might have had an impact on human development, but this thing has been around infecting lots of humans for millennia, so it's not like it's gonna suddenly start causing problems. You might as well panic about the incredibly common gene that cuts 4 years off your life.

# ? Oct 22, 2014 17:28

Xibanya: Sep 17, 2012; Clever Betty

Irony Be My Shield posted:

It's interesting that this parasite might have had an impact on human development, but this thing has been around infecting lots of humans for millennia, so it's not like it's gonna suddenly start causing problems. You might as well panic about the incredibly common gene that cuts 4 years off your life.

gene is a funny way to spell chromosome

# ? Oct 22, 2014 18:20

FRINGE: May 23, 2003; title stolen for lf posting

:catpeople:

http://blogs.scientificamerican.com/science-sushi/2012/07/04/toxoplasmas-dark-side-the-link-between-parasite-and-suicide/

quote:

The results were clear. Women with Toxoplasma infections were 54% more likely to attempt suicide � and twice as likely to succeed. In particular, these women were more likely to attempt violent suicides (using a knife or gun, for example, instead of overdosing on pills). But even more disturbing: suicide attempt risk was positively correlated with the level of infection. Those with the highest levels of antibodies were 91% more likely to attempt suicide than uninfected women. The connection between parasite and suicide held even for women who had no history of mental illness: among them, infected women were 56% more likely to commit self-directed violence.

While these results might seem frightening, they make sense when you think about how Toxoplasma is known to affect our personalities. In 2006, researchers linked Toxoplasma infection to neuroticism in both men and women. Neuroticism � as defined by psychology � is the �an enduring tendency to experience negative emotional states,� including depression, guilt and insecurity. The link between neuroticism and suicide is well established, thus if the parasite does make people more neurotic, it�s not surprising that it influences rates of self-violence.

http://scienceblogs.com/gregladen/2008/03/13/good-news-on-toxoplasmosis-tre/

quote:

An infected cat can excrete up to 20 million oocysts over two weeks�Even a single oocyst is infectious and they can remain infectious in water for up to six months and in warm moist soil for up to a year.

# ? Oct 23, 2014 11:33