Jaroslav Flegr isn't any unusual person. And yet, for years, he suspected his mind had been confiscated by parasites that had invaded his brain. therefore the prolific scientist took his science-fiction hunch into the work. What he’s currently discovering can startle you. may little organisms carried by house cats be locomotion into our brains, inflicting everything from automotive wrecks to schizophrenia?
NO ONE WOULD accuse Jaroslav Flegr of being a conformist. A self-described “sloppy dresser,” the 53-year-old Czech man of science has the contemplative air of somebody routinely lost in thought, and his still-youthful, square-jawed face is framed by kinky red hair that encircles his head sort of a ring of the fireside.
Certainly, Flegr’s thinking is jarringly unconventional. beginning in the early Nineties, he began to suspect that a acellular parasite within the protozoan family was subtly manipulating his temperament, inflicting him to behave in strange, usually suicidal ways that. And if it absolutely was messing together with his mind, he reasoned, it absolutely was most likely doing identical to others.
The parasite, that is excreted by cats in their BM, is termed Toxoplasma gondii(T. gondii or Toxo for short) and is that the germ that causes toxoplasmosis—the reason pregnant ladies square measure told to avoid cats’ litter boxes. Since the Nineteen Twenties, doctors have recognized that a lady WHO becomes infected throughout gestation will transmit the malady to the vertebrate, in some cases leading to severe brain harm or death. T. gondii is additionally a serious threat to folks with weakened immunity: within the youth of the AIDS epidemic, before smart antiretroviral medication was developed, it absolutely was guilty of the dementedness that afflicted several patients at the disease’s finish stage. Healthy kids and adults, however, sometimes expertise nothing worse than transient flu-like symptoms before quickly fighting off the protozoan, that thenceforth lies dormant within brain cells—or a minimum of that’s the quality medical knowledge.
But if Flegr is correct, the “latent” parasite could also be quietly tweaking the connections between our neurons, dynamical our response to scary things, our trust in others, however outgoing we have a tendency to square measure, and even our preference surely scents. And that’s not all. He additionally believes that the organism contributes to automotive crashes, suicides, and mental disorders like dementia praecox. after you add up all the various ways that it will damage the USA, says Flegr, “Toxoplasma would possibly even kill as many folks as protozoal infection or a minimum of 1,000,000 folks a year.”
An organic process scientist at Charles University in Praha, Flegr has pursued this theory for many years in relative obscurity. as a result of the struggles 7-with English and isn't abundant of a verbalizer even in his native tongue, he seldom travels to scientific conferences. That “maybe one in every one of the explanations my theory isn't higher glorious,” he says. And, he believes, his views could invite established opposition. “There is robust psychological resistance to the likelihood that human behavior will be influenced by some stupid parasite,” he says. “Nobody likes to desire a puppet. Reviewers [of my scientific papers] could are pained.” Another a lot of obvious reason for resistance, of course, is that Flegr’s notions sound associate awful heap like fringe science, right up there with shadow sightings and claims of dolphins telepathically act with humans.
But when years of being unheeded or discounted, Flegr is setting out to gain honourableness. Psychedelic as his claims could sound, several researchers, together with such huge names in neurobiology as Stanford’s Robert Sapolsky, suppose he may otherwise be onto one thing. Flegr’s “studies square measure well conducted, and that I will see no reason to doubt them,” Sapolsky tells American state. Indeed, recent findings from Sapolsky’s work and British teams counsel that the parasite is capable of extraordinary shenanigans. T. gondii, reports Sapolsky, will flip a rat’s robust innate aversion to cats into the associate attraction, luring it into the jaws of its No. 1 predator. Even a lot of superb is, however, it will this: the organism rewires circuits in elements of the brain that upset such primal emotions as concern, anxiety, and arousal. “Overall,” says Sapolsky, “this is wild, freaky biology.” Another tutorial heavyweight WHO takes Flegr seriously is that the dementia praecox knowledgeable E. Fuller Torrey, director of the Stanley Medical analysis Institute, in Maryland. “I admire Jaroslav for doing [this research],” he says. “It’s clearly not correctness, within the sense that not several labs do it. He’s done it totally on his own, with little or no support. I believe it bears staring at. I notice it fully credible.”
What’s a lot of, several specialists suppose T. gondii could also be far away from the sole microscopic performer capable of propulsion our strings. “My guess is that there square measure scads a lot of samples of this occurring in mammals, with parasites we’ve ne'er even detected,” says Sapolsky.
Familiar to most people, of course, is that the hydrophobia virus. On the verge of killing a dog, bat, or alternative homoiothermic host, it stirs the animal into a rage whereas at the same time migrating from the systema nervosum to the creature’s secretion, making certain that once the host bites, the virus can carry on in an exceedingly new career. however apart from hydrophobia, stories of parasites commandeering the behavior of large-brained mammals square measure rare. The way more common victims of parasitic mind control—at least those we all know about—are fish, crustaceans, and legions of insects, in step with Janice Moore, a behavioral scientist at Colorado State University. “Flies, ants, caterpillars, wasps, you name it—there square measure truckloads of them behaving weirdly as a result of parasites,” she says.
Consider Polysphincta gutfreundi, a parasitic wasp that grabs hold of the associate orb spider and attaches a small egg to its belly. A cringing animal emerges from the egg, then releases chemicals that prompt the spider to abandon weaving its acquainted spiral internet and instead spin its silk thread into a special pattern that may hold the cocoon within which the animal matures. The “possessed” spider even crochets a particular geometric style within the web, camouflaging the cocoon from the wasp’s predators.
Flegr himself traces his life’s work to a different master of mind management. nearly thirty years past, as he was reading a book by the British organic process scientist Richard Dawkins, Flegr was captivated by a passage describing, however, a worm turns associate hymenopter into its slave by incursive the ant’s systema nervosum. A drop in temperature unremarkably causes ants to go underground, however, the infected insect instead climbs to the highest of a blade of grass and clamps down thereon, turning into straightforward prey for a grazing sheep. “Its mandibles really become latched in this position, thus there’s nothing the hymenopter will do except suspend there within the air,” says Flegr. The sheep graze on the grass and chuck the ant; the worm gains entrance into the ungulate’s gut, that is strictly wherever it must be so as to complete—as the Lion King song goes—the circle of life. “It was the primary I learned regarding this type of manipulation, thus it created an enormous impression on American state,” Flegr says.
After he browses the book, Flegr began to create an affiliation that, he promptly admits, others would possibly notice crazy: his behavior, he noticed, shared similarities therewith of the reckless hymenopter. as an example, he says, he thought nothing of crossing the road within the middle of dense traffic, “and if cars honked at American state, I didn’t leap out of the means.” He additionally created no effort to cover his scorn for the Communists WHO dominated Czechoslovakia for many of his early adulthood. “It was terribly risky to overtly speak your mind at that point,” he says. “I was lucky I wasn’t confined.” and through a quest stint in Japanese Turkey, once the strife-torn region of erupted in the shot, he remembers being “very calm.” In distinction, he says, “my colleagues were panic-stricken. I puzzled what was wrong with myself.”
His disarray continued till 1990, once he joined the biology college of Charles University. because it happened, the 650-year-old establishment had long been a world leader in documenting the health effects of T. gondii, further as developing strategies for detective work the parasite. In fact, even as Flegr was inbound, his colleagues were sorting out infected people on whom to check their improved diagnostic kits, that is, however, he came to be asked in some unspecified time in the future to roll up his sleeve and gift blood. He discovered that he had the parasite—and simply probably, he thought, the key to his problematic suicidal streak.
He delved into T. gondii’s life cycle. when associate infected cat defecates, Flegr learned, the parasite is often picked up from the soil by scavenging or grazing animals—notably rodents, pigs, and cattle—all of that then harbor it in their brain and alternative body tissues. Humans, on the opposite hand, square measure exposed not solely by returning into contact with litter boxes, but also, he found, by beverage contaminated with cat BM, feeding unwashed vegetables, or, particularly in Europe, by overwhelming raw or undercooked meat. thence the French, in step with Flegr, with their love of cut ready saignant—literally, “bleeding”—can have infection rates as high as fifty-five p.c. (Americans are going to be happy to listen to that the parasite resides in so much fewer of them, tho' a still substantial portion: ten to twenty p.c.) Once within the associate animal or human host, the parasite then must revisit into the cat, the sole place wherever it will sexually reproduce—and this is often once, Flegr believed, behavioral manipulation would possibly get play.
The parasite T. gondii, seen here, could also be dynamical connections between our neurons, sterilization, however, we have a tendency to act and feel. (Dennis Kunkel Microscropy, Inc./Visuals Unlimited/Corbis Images)
Researchers had already ascertained a number of peculiarities regarding rodents with T. gondii that bolstered Flegr’s theory. The infected rodents were way more active in running wheels than clean rodents were, suggesting that they'd be more-attractive targets for cats, that square measure drawn to fast-moving objects. They additionally were less cautious of predators in exposed areas. Little, however, was glorious regarding however the latent infection would possibly influence humans, as a result of we have a tendency to and alternative giant mammals were wide plausible to be accidental hosts, or, as scientists square measure keen on putt it, a “dead end” for the parasite. however even though we have a tendency to were ne'er a part of the parasite’s life cycle, Flegr reasoned, mammals from mouse to man share the overwhelming majority of their genes, thus we would, in an exceedingly case of mistaken identity, still be prone to manipulations by the parasite.
In the Soviet-stunted economy, animal studies were means on the far side Flegr’s analysis budget. however luckily for him, thirty to forty p.c of Czechs had the latent sort of the malady, thus many students were out there “to function all-time low experimental animals.” He began by giving them and their parasite-free peer's standardized temperament tests—an cheap, if somewhat crude, the methodology of measure variations between the teams. additionally, he used a computer-based check to assess the reaction times of participants, WHO were schooled to press a button as shortly as a white sq. popped up anyplace against the dark background of the monitor.
The subjects WHO tested positive for the parasite had considerably delayed reaction times. Flegr was particularly stunned to be told, though, that the protozoan gave the impression to cause several sex-specific changes in temperament. Compared with clean men, males WHO had the parasite were a lot of self-examining, suspicious, oblivious to alternative people’s opinions of them, and inclined to disregard rules. Infected ladies, on the opposite hand, bestowed in just the alternative way: they were a lot of outgoing, trusting, image-conscious, and rule-abiding than clean ladies.
The findings were thus freaky that Flegr at first assumed his information should be blemished. thus he tested alternative groups—civilian and military populations. Again, identical results. Then, in search of a lot of evidence, he brought subjects certain more observation and battery of tests, within which they were rated by somebody blind to their infection standing. To assess whether or not participants valued the opinions of others, the rater judged however well dressed they gave the impression to be. As a life of sociability, participants were asked regarding the number of friends they’d interacted with over the past time period. to check whether or not they were vulnerable to being suspicious, they were asked, among alternative things, to drink the associate unidentified liquid.
The results meshed well with the form findings. Compared with clean folks of identical sex, infected men were a lot of possibilities to wear rumpled previous clothes; infected ladies attended to be a lot of meticulously clad, several disclosures for the study in high-priced, designer-brand consumer goods.
Infected men attended have fewer friends, whereas infected ladies attended have a lot of. And once it came to Andrew Jackson Downing the mystery fluid, reports Flegr, “the infected males were way more hesitant than clean men. They wished to grasp why they'd to try and do it. wouldn't it damage them?” In distinction, the infected ladies were the foremost trusting of all subjects. “They simply did what they were told,” he says.
Why men and ladies reacted thus otherwise to the parasite still metagrobolised him. when consulting the psychological literature, he began to suspect that heightened anxiety could be the common divisor underlying their responses. once beneath emotional strain, he read, ladies obtain solace through social bonding and nurturing. within the slang of psychologists, they’re inclined to “tend and bond.” Anxious men, on the opposite hand, usually respond by retreating and turning into hostile or delinquent. maybe he was staring at flip sides of the identical coin.
Closer examination of Flegr’s reaction-time results unconcealed that infected subjects became less attentive and over-involved a moment roughly into the check. This prompt to him that Toxoplasma may need associate adverse impact on driving, wherever constant vigilance and quick reflexes square measure essential. He launched 2 major medical specialty studies within the Czech Republic, one in every of men and ladies within the general population and another of principally male drivers within the military. people who tested positive for the parasite, each study showed, were regarding 2 and 0.5 times as possible to be in an exceeding traffic accident as their lean peers.
WHEN I MET Flegr for the primary time, last September, at his workplace on the third floor of Charles University’s Biological Sciences building, I used to be expecting one thing of a primitive.
however, once you get past the riotous red hair, his vogue is inconspicuous. skinny and slight of build, he’s soft, precise together with his facts, and—true to his Toxo status—clad in previous sneakers, light bottomed jeans, and a baggy button-up shirt. As our language issue, I discover that his latest findings have become—to quote Alice in Wonderland—“curiouser and curiouser,” which can justify why his forehead has the deep ruts of a chronic killjoy, or somebody constantly puzzled.
He’s revealed some information, he tells American state, that counsel infected males may need elevated androgen levels. probably for that reason, ladies showed photos of those men rate them as a lot of masculine than photos of clean men. “I wish to analyze this a lot of closes to ascertain if it’s true,” he says. “Also, it might be ladies notice infected men a lot of enticing. That’s one thing else we have a tendency to hope to check.”
Meanwhile, 2 Turkish studies have replicated his studies linking Toxoplasma to traffic accidents. With up to a simple fraction of the globe infected with the parasite, Flegr currently calculates that T. gondii may be a possible consider many hundred thousand road deaths every year. additionally, reanalysis of his personality-questionnaire information unconcealed that, rather like him, several people WHO have the latent infection feel unfearing in dangerous things. “Maybe,” he says, “that’s another excuse they get into traffic accidents. They don’t have a traditional concern response.”
It’s nearly not possible to listen to regarding Flegr’s analysis while not curious whether or not you’re infected—especially if, like me, you’re a cat owner, favor terribly rare meat, and determine even to a small degree bit along with your Toxo sex stereotype. thus before returning to Praha, I’d get tested for the parasite, however, I didn’t nevertheless recognize the results. It appeared a decent time to ascertain what his intuition would tell American state. “Can you guess from observant somebody whether or not they have the parasite—myself, for example?,” I ask.
“No,” he says, “the parasite’s effects on temperament square measure terribly delicate.” If, as a woman, you were self-examining before being infected, he says, the parasite won’t flip you into a raving extrovert. it would simply cause you to a small degree less self-examining. “I’m terribly typical of Toxoplasma males,” he continues. “But I don’t recognize whether or not my temperament traits have something to try and do with the infection. It’s not possible to mention for anybody individual. you always want regarding fifty {people WHO|people that|folks that|those that|those who} square measure infected and fifty who aren't, so as to ascertain a statistically important distinction.
The overwhelming majority of individuals can haven't any plan they’re infected.”
Still, he concedes, the parasite might be terribly dangerous news for the little proportion of people—and not simply people who could be at larger risk for automotive accidents. several dementia praecox patients show shrinkage in elements of their pallium, and Flegr thinks the protozoan could also be guilty of that. He hands American state a recently revealed paper on the subject that he co-authored with colleagues at Charles University, together with a shrink named Jiri Horacek. Twelve of forty-four dementia praecox patients WHO underwent tomography scans, the team found, had reduced nervous tissue within the brain—and the decrease occurred nearly solely in people who tested positive for T. gondii. when reading the abstract, I have to look shocked, as a result of Flegr smiles and says, “Jiri had the identical response. I don’t suppose he believed it might be true.” after I later speak with Horacek, he admits to having been skeptical regarding Flegr’s theory at the first. after they unified the tomography results with the infection information, however, he went from being a doubter to being a believer. “I was astounded at however pronounced the impact was,” he says. “To American state that means the parasite could trigger dementia praecox in genetically vulnerable folks.”
One could be tempted to dismiss the majority of Flegr’s work as hokum—the fanciful imaginings of a lone, eccentric scholar—were it not for the pioneering analysis of Joanne Webster, a parasitologist at Imperial school London. even as Flegr was embarking on his human trials, Webster, then a freshly minted hydrogen ion concentration.D., was launching studies of Toxo-infected rodents, reasoning, even as Flegr did, that as hosts of the parasite, they'd be possible targets for behavioral manipulation.
She quickly confirmed, as previous researchers had shown, that infected rats were a lot of active and fewer cautious in areas wherever predators lurk. But then, in an exceedingly straightforward, elegant experiment, she and her colleagues incontestable that the parasite did one thing way more outstanding. They treated one corner of every rat’s enclosure with the animal’s own odor, a second with water, a 3rd with cat piss, and therefore the last corner with the piss of a rabbit, a creature that doesn't go after rodents. “We thought the parasite would possibly scale back the rats’ aversion to cat odor,” she told American state. “Not solely did it try this, however, it really exaggerated their attraction. They spent longer within the cat-treated areas.” She and alternative scientists perennial the experiment with the piss of dogs and minks, that additionally go after rodents. The impact was thus specific to cat piss, she says, that “we decided it ‘fatal feline attraction.’”
She began tagging the parasite with fluorescent markers and chase its progress within the rats’ bodies. Given the surgically precise means the germ alters behavior, Webster anticipated that it might find yourself in localized regions of the brain. however, the results defied expectations. “We were quite stunned to search out the cysts—the parasite’s dormant form—all over the brain in what otherwise gave the impression to be a contented, healthy rat,” she says. nevertheless, the cysts were most galore in an exceedingly a part of the brain that deals with pleasure (in human terms, we’re talking sex, drugs, and rock and roll) and in another space that’s concerned in concern and anxiety (post-traumatic stress disorder affects this region of the brain). Perhaps, she thought, T. gondii uses an undiscriminating approach, distributive cysts so much and wide, facultative a number of-them to zero in on the correct targets.
To gain a lot of clarity on the matter, she sought-after the help of the parasitologist cosmonaut McConkey, whose team at the University of the city was inquiring the protozoan’s ordering for signs of what it would be doing. The approach dropped at lightweight a hanging talent of the parasite: it's 2 genes that permit it to crank up production of the neurochemical monoamine neurotransmitter within the host brain. “We ne'er stop to be astounded by the sophistication of those parasites,” Webster says.
Their findings, reported last summer, created immediate buzz. monoamine neurotransmitter may be an essential signal molecule concerned with concern, pleasure, and a spotlight. moreover, the neurochemical is understood to be jacked up in folks with schizophrenia—another one in every one of those strange observations regarding the malady, like its tendency to erode nervous tissue, that has long nonplused medical researchers. ataractic drug medication designed to quell schizophrenic delusions apparently blocks the action of monoamine neurotransmitter, that had prompt to Webster that what it would very be doing is thwarting the parasite. Scientists had already shown that adding the drugs to a dish wherever T. gondii is jubilantly dividing can stunt the organism’s growth. thus Webster determined to feed the neuroleptic to freshly infected rats to ascertain however they reacted. Lo, and lay eyes on, they didn’t develop the fatal feline attraction. Suddenly, attributing behavioral changes to the germ appeared way more plausible.
As the scientific community digestible the British team’s monoamine neurotransmitter discoveries, Robert Sapolsky’s work at Stanford declared still a lot of attention-grabbing news. The neurobiologist and his colleagues found that T. gondii disconnects concern circuits within the brain, which could facilitate to elucidate why infected rats lose their aversion to cat odor. even as surprising, reports Sapolsky, the parasite at the same time is “able to hijack a number of the electronic equipment associated with sexual arousal” within the male rat—probably, he theorizes, by boosting monoamine neurotransmitter levels within the reward-processing a part of the brain. thus once the animal catches a whiff of cat scent, the concerned center fails to totally illumine because it would in an exceedingly traditional rat, and instead, the realm governing pleasure begins to glow. “In alternative words,” he says, “Toxo makes cat odor smell attractive to male rats.”
The biologist Ajai Vyas, when operating with Sapolsky on this study as a postdoctoral student, determined to examine infected rats’ testicles for signs of cysts. for sure, he found them there—as well as within the animals’ cum. And once the rat copulates, Vyas discovered, the protozoan moves into the female’s female internal reproductive organ, usually infecting sixty p.c of her pups, before traveling on up to her own brain—creating still a lot of vehicles for the ferry the parasite into the belly of a cat.
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