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Parasites Makes Us Dumber or Sexier
odie_q writes "It has long been known that the Toxoplasma gondii parasite alters its host's behavior, but now it seems the way it alters it depends on the sex of the host. From the article: 'A common parasite can increase a women's attractiveness to the opposite sex but also make men more stupid, an Australian researcher says ... Infected men have lower IQs, achieve a lower level of education and have shorter attention spans. They are also more likely to break rules and take risks, be more independent, more anti-social, suspicious, jealous and morose, and are deemed less attractive to women. On the other hand, infected women tend to be more outgoing, friendly, more promiscuous, and are considered more attractive to men compared with non-infected controls.'"
Clearly, this is a textbook case of toxoplasmosis. You should keep your hands out of the litter box.
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I believe this is one of those news stories that sits around waiting for a slow news day. The original paper was released in November. It's written by Kevin Lafferty and was published in Proc. Roy. Soc. B.
It's a really quite fascinating paper - I recommend tracking it down if you can get access. Here's how it goes: Toxoplasmia gondii is adapated to live in cats and reproduces in felid intestinal cells & is shed, encysted, in their feaces. Then it can directly infect cats who come into contact with the cysts, or it encysts in brains of smaller mammals, and moves up the food chain as they get eaten until it hits a cat, and can reproduce again.
Fascinatingly, T.g. appears to affect rodent behavior to increase predation risk - i.e. the rodents become more active, less fearful of cat/cat smells, and have increased dopamine levels (which supposedly leads to novelty seeking behavior and neuroticism-type behaviors, or at least, they do in humans).
Despite humans not having any major cat predators, it could still affect us as a byproduct type of thing. Particularly that whole dopamine increase - this is should increase neuroticism levels.
So - the big question - does prevalence of T.g. correlate with cultural variation in neuroticism in humans? Lafferty finds a fairly strong correlation ( r2 of 0.38 ) between population aggregate neuroticism (as measured by the fairly standard NEO PI-R personality inventory ).
Unfortunately I think the populations he uses for his stats are a little bit suspect (always the problem with worldwide analyses though), but it's definitely worth a read. You should also keep in mind that so far it's only an interesting correlation and not a direct demonstration that T.g. causes large scale cultural differences.
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The article clearly states that the changed behaviour could be seen after infecting the mice with toxoplasmose and be reversed by treating the infection. So we have something that looks a lot more like a causation and less a pure correlation (with currently unknown relation).
"A common parasite can increase a women's attractiveness to the opposite sex but also make men more stupid"
What do you mean by more stupid?
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...infected women tend to be more outgoing, friendly, more promiscuous, and are considered more attractive to menPerhaps it's just me, but my first thought after reading the summary was that the best and brightest the world of cosmetics marketing has to offer are probably working on the advertising campaign right now. "New, from L'Oreal: toxoplasmosis, the only parasite derived from cat shit that's /guaranteed/ to make you MORE ATTRACTIVE to the opposite sex. Because you're worth it!"...
Given the crap they already get women to shell out fifty quid for a couple of ounces, parasite-infected cat shit would be a relatively easy sell.
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Damn you're sexy, you have parasites don't you ?
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Sorry, bad formatting, let's try this again...
How do you like your steak? Unless your answer is "well done", you are at greater risk for toxoplasmosis than any cat owner.
From wikipedia: "The most common means of transmission to humans is raw or undercooked meat."
Further, based on research it is *extremely* unlikely that you could pick up this parasite from casual contact with cats. Handling cat feces and not washing your hands? Sure. Petting a cat? No way.
From wikipedia: "Although the pathogen has been detected on the fur of cats, it has not been found in an infectious form, and direct infection from handling cats is generally believed to be very rare."
Further, cats must contract the disease from somewhere and are only infectious for a brief period right after contracting the disease. Which means that indoor cats that don't have access to infected prey can't get the disease (except by other transmission methods which are the same for humans). Or, if your cat already has toxoplasmosis, it means that it can't transmit the parasite to you (except for that brief period right after infection.
From wikipedia: "Cats excrete the pathogen in their faeces for a number of weeks after contracting the disease, generally by eating an infected rodent. Even then, cat faeces are not generally contagious for the first day or two after excretion, after which the cyst 'ripens' and becomes potentially pathogenic. Studies have shown that only about 2% of cats are shedding at any one time, and that shedding does not recur even after repeated exposure to the parasite."
Further, the disease *is* treatable. The cysts are resistant to common forms of treatment for parasites (antibiotics). However, there are treatments available which seem to eliminate the cysts.
From wikipedia: "The antibiotic atovaquone has been used to kill Toxoplasma cysts in situ in AIDS patients.[3] In mice, a combination of atovaquone with clindamycin seemed to optimally kill cysts."
Here is a link to wikipedia: http://en.wikipedia.org/wiki/Toxoplasmosis
Every time a toxoplasmosis article comes up, someone will make a post like this, saying that *for them* cat ownership is simply too risky. This, of course, completely ignores the reality of the situation, where cat ownership is actually far less risky than eating, where mishandling of food or "undercooked" meat (may I be the first to say, yum!) are far more likely to score you an infectious parasite.
Please inform yourself and stop spouting this trollish bullshit.
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