Listen to this PodcastMore 60-Second Science
When a healthy rat smells a cat, it flees. But rats infected with the Toxoplasma brain parasite actually follow cat odors, often presumably to their doom, red in tooth and claw. Now researchers have found out exactly what’s going on in the rat’s infected brain—it’s in love. The study is in the journal Public Library of Science ONE. [Patrick K. House, Ajai Vyas and Robert Sapolsky, "Predator Cat Odors Activate Sexual Arousal Pathways in Brains of Toxoplasma gondii Infected Rats"]
That Toxo-infected rats approach cats has long been a well-known example of a parasite manipulating the behavior of its mammalian host. The protozoan needs to be in a cat’s intestine to reproduce. It then gets pooped out and has to find its way into another cat to continue its fabulously glamorous lifestyle. Rats that touch the poop and then get eaten by a cat can complete the circuit.
The new research reveals that when a Toxo-infected rat smells cat urine, it has increased activity in brain regions associated with sexual attraction. Which the researchers say is “compelling evidence that Toxoplasma overwhelms the innate fear response by causing, in its stead, a type of sexual attraction to the normally aversive cat odor.” That’s right, the rat is turned on. Before it’s permanently turned off.
—Steve Mirsky
[The above text is a transcript of this podcast.]
See what we're tweeting about
11 Comments
Add CommentToxoplasmosis is a major problem in society because it is estimated that some 11 million Americans are infected with it. Recent work at the University of Leeds has found that the parasite produces an enzyme with tyrosine hydroxylase and phenylalanine hydroxylase activity. This enzyme may contribute to the behavioral changes observed in toxoplasmosis by altering the production of dopamine, a neurotransmitter involved in mood, sociability, attention, motivation and sleep patterns. Schizophrenia has long been linked to dopamine dysregulation.
Reply | Report Abuse | Link to thisHowever, in that a rodent brain in many ways is similar to a human brain, it raises the striking question that those who believe "we should love our enemies", might only believe so because they are infected with a mind manipulating parasite.
As such it is essential that such people be identified, and their parasites eliminated.
Hey Steve Mirsky the link has come:
Reply | Report Abuse | Link to thishttp://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0023277
Since animals rely overwhelmingly on their sense of smell, then chemical odors would stimulate the production of dopamine. Apparently, toxoplasmosis can modify a signal that should trigger anxiety into one that triggers pleasure. But does it really explain why beautiful women are attracted to tattoo-covered trailer trash?
Reply | Report Abuse | Link to thisWe know that a lot of substances, like cocaine and opiates, lead to obsessive, desperate behavior characterized by the single-minded pursuit of the substance itself, at the cost of all else. Thus, the lack of the stimulus rather than the presence of it is the cause of risk-taking and recklessness. Middle-aged men being "led by the nose" by a pretty young thing? The same man, 30 years prior, would have "vehemently" protested the same girl's financial demands. Loneliness by itself leads to an unbearable, torturous life, only to be made worse by substance abuse. According to Shakespeare, tragedy is the unavoidable norm by which all human lives are governed. Therefore, we do not love our enemies because of some strange infection, but rather because our monetarized lifestyles prevents us from associating with or trusting anyone, leading eventually to ignore obvious danger signals. The SS troops in Nazi Germany wore the "death's head" emblem on their uniforms, yet that didn't deter millions of Jews from sticking around until the very end.
Let's teach our children to avoid danger through Biblical proverbs rather than trying to find a cure for toxoplasmosis.
Thanks for the link!
Reply | Report Abuse | Link to thisOBagle - did you miss the "Scientific America" sign on the door?
Reply | Report Abuse | Link to this@aQuah8x: "...those who believe 'we should love our enemies', might only believe so because they are infected with a mind manipulating parasite." - So when Jesus was going on about "turning the other cheek" and all that, it was really just the toxo talking?
Reply | Report Abuse | Link to this@OBagle: (a)"Middle-aged men being 'led by the nose' by a pretty young thing?" - That doesn't require a mind-altering in fection or "monetarized lifestyles", it's a simple matter of biology. The young girl is more likely to be fertile that a woman his own age, so the man's reproductive instincts naturally draw him to her. Some men can repress millions of year of evolution telling them to spread their genes to a new generation, others (most?) can't.
(b) "Let's teach our children to avoid danger through Biblical proverbs rather than trying to find a cure for toxoplasmosis." - Because no one's ever done anything dumb or dangerous in the name of religion, right?
and (c) What do have against tattoos?
Fascinating behaviour! But how could this have possibly evolved? It obviously did, but how? The suggestion provided in this article is, in my opinion, hardly adequate.
Reply | Report Abuse | Link to thisa very funny research
Reply | Report Abuse | Link to thisThe very real mystery of Toxoplasma gondii's effect on rats and people is tackled by fictional characters in a new book entitled, Purr, the novel, by F. Wyman Morgan. See an extensive preview at purrthenovel.com. Purchase from Amazon.com. An assistant professor, with a well-deserved reputation as a womanizer, undertakes a program to study Toxoplasma gondi and "solves" the riddle of how the microbe makes rats suicidal and women amorous
Reply | Report Abuse | Link to thisWhat a way to reduce rat populations,just introduced toxoplasma to a problem area.The only problem might be cross contamination with people.Is this why cat people love their cats,and others can't stand the smell?I have seen some very big rats.Could rats raping cats become a problem?Talk about your weird offspring.If it were possible?Could make for a good movie maybe named Crats.
Reply | Report Abuse | Link to thisI like cats, but far away from me; rats, I dislike in every circumstance.
Reply | Report Abuse | Link to thisCats, I repute them neurotics; rats, I find that are loathsome.
Yep, I think that the tummy of a cat is a good place for a rat!
But the scientists are saying that the poop of cats could represent danger for us humans, in the form of an illness named toxoplasmosis! This is one more reason to keep my choice not to have cats as pets.
We can encounter also at *EurekAlertA* a very interesting reading (if complementary or supplementary, you decide) about this theme.
http://www.eurekalert.org/pub_releases/2011-08/su-put081911.php