By min | March 2, 2012, 3:59 PM | My Dreams| Link

Beware the Cat Poo Parasite

Fnord12 was kind enough to send this to me. All i can say is "Thanks, Mom, for thinking pets are gross and dirty and never allowing us to have them."

Jaroslav Flegr is an evolutionary biologist at Charles University in Prague. The parasite mentioned in the following paragraph is Toxoplasma gondii and is excreted by cats in their poo.

Starting in the early 1990s, he began to suspect that a single-celled parasite in the protozoan family was subtly manipulating his personality, causing him to behave in strange, often self-destructive ways. And if it was messing with his mind, he reasoned, it was probably doing the same to others. ... After an infected cat defecates, Flegr learned, the parasite is typically picked up from the soil by scavenging or grazing animals--notably rodents, pigs, and cattle--all of which then harbor it in their brain and other body tissues. 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.) Once inside an animal or human host, the parasite then needs to get back into the cat, the only place where it can sexually reproduce--and this is when, Flegr believed, behavioral manipulation might come into play.

20% of Americans. That's 1 in 5 people. I know more than 5 people!

If you keep reading, his kooky idea doesn't sound as kooky as it does at first blush. But before we all get panicky about the parasitic cysts in our brains (and possibly our reproductive organs), i'll be kind and give you the "Don't Panic" info that's thrown in towards the end of the article.

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. During that brief period, Flegr simply recommends taking care to keep kitchen counters and tables wiped clean...Much more important for preventing exposure, he says, is to scrub vegetables thoroughly and avoid drinking water that has not been properly purified, especially in the developing world, where infection rates can reach 95 percent in some places. Also, he advises eating meat on the well-done side--or, if that's not to your taste, freezing it before cooking, to kill the cysts.

Although, how do you know your indoor cat didn't get exposed to it prior to you getting it? And please, let's just be frank here. Poo is poo, whether or not it's infected with a parasite. So, you know, ew.

Ok, now on to the more horrific bits and pieces of parasites and how they make you do shit.

We start with the things it does in rats. The parasite can only reproduce in cats. They've found that rats infected with the parasite have had their brains rewired in such a way that they become less fearful of cats.

T. gondii, reports Sapolsky, can turn a rat's strong innate aversion to cats into an attraction, luring it into the jaws of its No. 1 predator. Even more amazing is how it does this: the organism rewires circuits in parts of the brain that deal with such primal emotions as fear, anxiety, and sexual arousal. ... Webster, then a freshly minted Ph.D., was launching studies of Toxo-infected rodents, reasoning, just as Flegr did, that as hosts of the parasite, they would be likely targets for behavioral manipulation.

She quickly confirmed, as previous researchers had shown, that infected rats were more active and less cautious in areas where predators lurk. But then, in a simple, elegant experiment, she and her colleagues demonstrated that the parasite did something much more remarkable. They treated one corner of each rat's enclosure with the animal's own odor, a second with water, a third with cat urine, and the last corner with the urine of a rabbit, a creature that does not prey on rodents. "We thought the parasite might reduce the rats' aversion to cat odor," she told me. "Not only did it do that, but it actually increased their attraction. They spent more time in the cat-treated areas." She and other scientists repeated the experiment with the urine of dogs and minks, which also prey on rodents. The effect was so specific to cat urine, she says, that "we call it 'fatal feline attraction.'"

The cysts tend to be most abundant in 2 areas of the brain. The one that deals with pleasure and the one that deals with fears and anxiety. And what exactly do they do? They are able to cause your body to increase dopamnine production. Little bastards.

The neuroscientist and his colleagues found that T. gondii disconnects fear circuits in the brain, which might help to explain why infected rats lose their aversion to cat odor. Just as startling, reports Sapolsky, the parasite simultaneously is "able to hijack some of the circuitry related to sexual arousal" in the male rat--probably, he theorizes, by boosting dopamine levels in the reward-processing part of the brain. So when the animal catches a whiff of cat scent, the fear center fails to fully light up, as it would in a normal rat, and instead the area governing sexual pleasure begins to glow. "In other words," he says, "Toxo makes cat odor smell sexy to male rats."

The neurobiologist Ajai Vyas, after working with Sapolsky on this study as a postdoctoral student, decided to inspect infected rats' testicles for signs of cysts. Sure enough, he found them there--as well as in the animals' semen. And when the rat copulates, Vyas discovered, the protozoan moves into the female's womb, typically infecting 60 percent of her pups, before traveling on up to her own brain--creating still more vehicles for ferrying the parasite back into the belly of a cat.

That's just so wrong.

Ok. Enough about rats. What does it do to people? As mammals, we do have quite alot of genetic similarities, after all. Does it make you love cats more? That would explain those crazy cat people...

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 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.

This is about when i told fnord12 that the Republicans should start a campaign to get a cat to every woman in America.

Because it affects the pleasure and anxiety portions of your brain, scientists believe it can trigger schizophrenia in people who are genetically susceptible. I would imagine it would exacerbate any mental/mood disorder, since many of them (bipolar disorder, depression, OCD, etc.) are all related in one way or another to pleasure, fear, anxiety, paranoia, etc.

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. ... Antipsychotic medicine designed to quell schizophrenic delusions apparently blocks the action of dopamine, which had suggested to Webster that what it might really be doing is thwarting the parasite. Scientists had already shown that adding the medicine to a petri dish where T. gondii is happily dividing will stunt the organism's growth. So Webster decided to feed the antipsychotic drug to newly infected rats to see how they reacted. Lo and behold, they didn't develop fatal feline attraction.

One psychiatrist even links the rise in the prevalence of schizophrenia with the increased popularity of keeping cats as pets.

The psychiatrist E. Fuller Torrey agrees--though he came to this viewpoint from a completely different angle than either Webster or Flegr. His opinion stems from decades of research into the root causes of schizophrenia. "Textbooks today still make silly statements that schizophrenia has always been around, it's about the same incidence all over the world, and it's existed since time immemorial," he says. "The epidemiology literature contradicts that completely." In fact, he says, schizophrenia did not rise in prevalence until the latter half of the 18th century, when for the first time people in Paris and London started keeping cats as pets. The so-called cat craze began among "poets and left-wing avant-garde Greenwich Village types," says Torrey, but the trend spread rapidly--and coinciding with that development, the incidence of schizophrenia soared.

Now, let's not get into a debate about causation vs correlation. Let's just agree that that's an interesting coincidence that bears more study.

According to Teodor Postolache, a psychiatrist and the director of the Mood and Anxiety Program at the University of Maryland School of Medicine, a flurry of other studies, several conducted by his own team, offers further support of T. gondii's link to higher rates of suicidal behavior. These include investigations of general populations as well as groups made up of patients with bipolar disorder, severe depression, and schizophrenia, and in places as diverse as Turkey, Germany, and the Baltimore/Washington area. Exactly how the parasite may push vulnerable people over the edge is yet to be determined. Postolache theorizes that what disrupts mood and the ability to control violent impulses may not be the organism per se, but rather neurochemical changes associated with the body's immune response to it.

The article mentions other horrible things that affect your brain and behavior and mentions parasites are everywhere even if we aren't aware of them. So we're basically fucked. Just roll with it.

Hey, but it's not all bad. Gentleman, if you've been having trouble attracting members of the fairer sex, have i got the answer for you!

Flegr's published some data, he tells me, that suggest infected males might have elevated testosterone levels. Possibly for that reason, women shown photos of these men rate them as more masculine than pictures of uninfected men. .. The researchers also discovered that infected male rats suddenly become much more attractive to females. "It's a very strong effect," says Vyas. "Seventy-five percent of the females would rather spend time with the infected male."

Huh, huh? Yeah, that's what i thought.