Scary Science Stories #3: The Mind Parasites

No this isn’t about Colin Wilson’s Lovecraftian novel The Mind Parasites. It’s about something else.

Suppose that there was a parasite that needed to get into the gut of a cat in order to complete its reproductive cycle.

How can this parasite get into the guts of cats?

Well, a good way would be by first infecting things that cats like to eat–like rats.

But cats don’t like to eat dead mice. They like to eat living ones.

So, if you’re the parasite, you want to do whatever you can to make sure that your mouse gets eaten before it dies a natural death and starts decaying.

The problem is that rats don’t like to be eaten by cats. In fact, they have a panic/avoidance reaction to cats. So strong is this reaction that the scent of cat urine produces a panic reaction (which human scientists use when they need to induce fear in rats) and they flee places cats have marked with cat urine.

If you’re the parasite, that’s no good for you. The rats have an inbuilt cat-avoidance mechanism.

But maybe you can disable it.

Let’s suppose that you form cysts in the rat’s body, including in its brain. Maybe you can turn off its panic/avoidance mechanism.

If so, then your rat will stop being afraid of places that cats have marked and will spend more time in places where cats hang out, thus increasing the chances that cats will eat them.

In fact, maybe you can get the rat to become attracted to the smell of cat urine, causing him to have a suicidal attraction to cats.

If so, good for you.

Now suppose also that you–this parasite–happen to also infect HALF of the human population.

And suppose that there is evidence linking you to schizophrenia in humans.

Is there such a parasite?

There is. It’s called toxoplasma gondii.

GET THE STORY.

MORE HERE.

Incidentally, the first story mentions several other behavior-altering parasites as well. It does not, however, mention one that I’m curious to know about.

A number of years ago I saw a documentary that talked about a parasite that infects snails and causes them to get eaten by birds. This parasite does two things: It makes the snail have a compulsion to crawl up onto the tops of leaves, so birds can see them, and it makes the snail pulse in weird colors–again to attract the bird’s attention.

If anybody knows the name of that parasite, please let me know.

Not that I have any snails I want to get rid of. It’s just hate not being able to remember the name of something so eerie.

Author: Jimmy Akin

Jimmy was born in Texas, grew up nominally Protestant, but at age 20 experienced a profound conversion to Christ. Planning on becoming a Protestant seminary professor, he started an intensive study of the Bible. But the more he immersed himself in Scripture the more he found to support the Catholic faith, and in 1992 he entered the Catholic Church. His conversion story, "A Triumph and a Tragedy," is published in Surprised by Truth. Besides being an author, Jimmy is the Senior Apologist at Catholic Answers, a contributing editor to Catholic Answers Magazine, and a weekly guest on "Catholic Answers Live."

16 thoughts on “Scary Science Stories #3: The Mind Parasites”

  1. The story seems a to be a good candidate for Intelligent Design (joking). It’s almost impossible to believe that a parasite would come up with such a clever scheme to get into a cat’s guts.

  2. You know, I saw a thing on Animal Planet the other night related to this. There’s some kind of bug similar to this that gets into the brains of ants so that they go an attach themselves to the tips of grass blades. They can sit there for weeks stuck because the bacteria impels them to stay latched on there. Then a bunny or some other rodent will eat the ant, and the bacteria will reproduce, spreading its eggs wherever the rodent goes. Then, the eggs get eaten by snails. The eggs hatch into larvae, which gum up the snail’s internal systems and makes it hack up snail phlegm (ew). The larvae get a ride out on the phlegm-mobile, and it just so happens that ants like to eat snail phlegm. The larvae infect the ant, and the lifecycle starts over again. Weird, eh?

  3. “The story seems a to be a good candidate for Intelligent Design (joking). It’s almost impossible to believe that a parasite would come up with such a clever scheme to get into a cat’s guts.”
    The same thing struck me, but it could be that in competition with other kinds of parasites, the ones mentioned in the article have more successfully reproduced partly BECAUSE of the effects thay have on the host’s behavior, rather than causing the behavior IN ORDER to reproduce.
    In other words, maybe the parasite just happens to cause bizarre behavior that coincidentally benefits both the parasite and the predator.
    This is also less scary by a factor of about twelve.
    Otherwise, I keep seeing these parasites as microscopic Stewie Griffins in the brain, going “Ye-e-esss, you like cat urine, don’t you? Do you smell the nice cat urine?”.

  4. I would think that, since animals do not have rational souls (as humans do), they do not have free will & operate purely on instinct.
    But I’m a bear of very little brain & this is just a guess!

  5. I work on the neuronal systems that underlie panic/fight or flight responses and have found this phenomena interesting. I wondered if, upon entering the brain, the toxoplasma gondii parasite was specifically invading regions associated with panic/fight or flight. I had to do some searching, but a recent article by a reknowned scientist (Dr. Sapolsky and colleagues from Stanford) has determined that the parasite seems to preferentially invade limbic brain regions such as the amydala which are involved in panic/fight or flight responses. In addition, the parasite does appear to make the rat attracted to the scent of cat urine. There are more interesting findings as well. See the abstract below.
    Proc Natl Acad Sci U S A. 2007 Apr 10;104(15):6442-7. Epub 2007 Apr 2. Links
    Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors.Vyas A, Kim SK, Giacomini N, Boothroyd JC, Sapolsky RM.
    Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. ajaivyas@stanford.edu
    The protozoan parasite Toxoplasma gondii blocks the innate aversion of rats for cat urine, instead producing an attraction to the pheromone; this may increase the likelihood of a cat predating a rat. This is thought to reflect adaptive, behavioral manipulation by Toxoplasma in that the parasite, although capable of infecting rats, reproduces sexually only in the gut of the cat. The “behavioral manipulation” hypothesis postulates that a parasite will specifically manipulate host behaviors essential for enhancing its own transmission. However, the neural circuits implicated in innate fear, anxiety, and learned fear all overlap considerably, raising the possibility that Toxoplasma may disrupt all of these nonspecifically. We investigated these conflicting predictions. In mice and rats, latent Toxoplasma infection converted the aversion to feline odors into attraction. Such loss of fear is remarkably specific, because infection did not diminish learned fear, anxiety-like behavior, olfaction, or nonaversive learning. These effects are associated with a tendency for parasite cysts to be more abundant in amygdalar structures than those found in other regions of the brain. By closely examining other types of behavioral patterns that were predicted to be altered we show that the behavioral effect of chronic Toxoplasma infection is highly specific. Overall, this study provides a strong argument in support of the behavioral manipulation hypothesis. Proximate mechanisms of such behavioral manipulations remain unknown, although a subtle tropism on part of the parasite remains a potent possibility.

  6. for SLalley.
    I read your posts and it came to mind that there was toxo research on tadpoles that showed a more complex relationship. That toxo load was looked at as a factor and an interesting difference was noted. High load tadpoles were better able to avoid predators while low load tadpoles seemed to be attracted to predators.
    Sort or a selective breeding situation.
    Perhaps a strong immune response triggers the “mmmm cat pee” alterations and a successful symbiosis is protected in an attempt to spread that immune trait in the gene pool. This would ensure that the apex host’s food can at any time needed, be driven to the host predator… One can see this type selection behaviour stronger in less advanced organisms like insects with wolbachia, as in an artificial barrier put in place in a type of wasp that causes a breeding barrier and a divergence into a new type of wasp.
    In regards to symbiotic prey.. Does the parasites apex host predator act different if it does get a high load prey? I wonder if high loads get a play response more often then a predatory one.
    I didn’t find that tadpole paper but I found this.
    The relationship between numbers of larvae recovered from the brain of Toxocara canis-infected mice and social behaviour and anxiety in the host
    http://journals.cambridge.org/action/displayAbstract;jsessionid=9AE612185AF119FA5460AA5AB87EBB8D.tomcat1?fromPage=online&aid=24123
    (Warning) I’m leaving the ground on this one.. but I like pondering this..
    I think even more important for you to keep in mind looking into toxo is how toxo can raise IQ’s or make a woman more attractive… IF there is no intelligence in toxo then how a smarter person? This seems to pass right by people… If you saw a monkey building a house you’d be amazed but what would you say if it was a better house then a person could build?
    We know a monkey is not more intelligent then us.. but do we know that of microbes? Consider that some protozoans have a genome 200 times the size of an Einstein and the rapid evolution we see in microbes. I find it perplexing that so many gloss over a microbe that can raise or lower a person intelligence. Perhaps it’s the implications to the human ego.
    (cost is clear)back to solid ground.
    I do access intelligence to microbes in complex systems like brains. Even one protozoan sucked up into an eyedropper can get out.. but if you suck it up again it gets out faster… That is learning…
    If you look at how complex bacteria colonies are then you get an added possibility to consider.
    “Bacterial linguistic communication and social intelligence”
    http://ctbp3.ucsd.edu:8080/pubpdf/427.pdf
    In this some individual bacteria act as translators between it’s bacteria and another group with a different linguistic group of bacteria,plant,animal..ext
    I’d note that I do see intelegent design in evolution, but I’d also say that I don’t see intelligence in those that talk about “Intelligent design” and push for it to be taught in schools.. Get my point?
    To the religious(warning again)..
    Kinda interesting that Rome found morality and became the center of Christianity as not long before they were “feeding Christians to lions” cough cough. But not being a religious person with interests in rituals and out dated conceptual interpretation I’m not going to talk much about that. Just a hint for you.

  7. I’d note that I do see intelegent [sic] design in evolution, but I’d also say that I don’t see intelligence in those that talk about “Intelligent design” and push for it to be taught in schools.. Get my point?
    I get the point that your enlightened mind can’t tolerate debate without insulting those whom you do not agree with. I believe that’s not how one wins, but how one forfeits a debate…
    Kinda interesting that Rome found morality and became the center of Christianity as not long before they were “feeding Christians to lions” cough cough.
    Don’t you mean “after they were feeding Christians to lions”?
    And why do you use scare quotes? What is with your “cough cough” addendum? Do you deny Christians were fed to lions? With all possible kindness, what do you mean?

Comments are closed.