Toxoplasma Gondii Parasite Mind Control

Half of the world's human population is infected with Toxoplasma. Parasites in the body - and the brain. Remember that.

Toxoplasma gondii is a common parasite found in the gut of cats; it sheds eggs that are picked up by rats and other animals that are eaten by cats. Toxoplasma forms cysts in the bodies of the intermediate rat hosts, including the brain. Since cats don't want to eat dead, decaying prey, Toxoplasma takes the evolutionarily sound course of being a "good" parasite, leaving the rats perfectly healthy. Or are they?

(Toxoplasma gondii)

Oxford scientists discovered that the minds of the infected rats have been subtly altered. In a series of experiments, they demonstrated that healthy rats will prudently avoid areas that have been doused with cat urine. In fact, when scientists test anti-anxiety drugs on rats, they use a whiff of cat urine to induce neurochemical panic. However, it turns out that Toxoplasma-ridden rats show no such reaction. In fact, some of the infected rats actually seek out the cat urine-marked areas again and again. The parasite alters the mind (and thus the behavior) of the rat for its own benefit.

If the parasite can alter rat behavior, does it have any effect on humans? Dr. E. Fuller Torrey (Associate Director for Laboratory Research at the Stanley Medical Research Institute) noticed links between Toxoplasma and schizophrenia in human beings, approximately three billion of whom are infected with T. gondii:

  • Toxoplasma infection is associated with damage to astrocytes, glial cells which surround and support neurons. Schizophrenia is also associated with damage to astrocytes.
  • Pregnant women with high levels of antibodies to Toxoplasma are more likely to give birth to children who will develop schizophrenia.
  • Human cells raised in petri dishes, and infected with Toxoplasma, will respond to drugs like haloperidol; the growth of the parasite stops. Haloperidol is an antipsychotic, used to treat schizophrenia.
Dr. Torrey got together with the Oxford scientists, to see if anything could be done about those parasite-controlled rats who were driven to hang around cat urine-soaked corners (waiting for cats). According to a recent press release, it turns out that haloperidol restores the rat's healthy fear of cat urine. In fact, antipsychotic drugs were as effective as pyrimethamine, a drug that specifically eliminates Toxoplasma.

Are parasites like Toxoplasma subtly altering human behavior? As it turns out, science fiction writers have been thinking about whether or not parasites could alter a human being's behavior, or even take control of a person. In his 1951 novel The Puppet Masters, Robert Heinlein wrote about alien parasites the size of dinner plates that took control of the minds of their hosts, flooding their brains with neurochemicals. In this excerpt, a volunteer strapped to a chair allows a parasite to be introduced; the parasite rides him, taking over his mind. Under these conditions, it is possible to interview the parasite; however, it refuses to answer until zapped with a cattle prod.

He reached past my shoulders with a rod. I felt a shocking, unbearable pain. The room blacked out as if a switch had been thrown.. I was split apart by it; for the moment I was masterless.

The pain left, leaving only its searing memory behind. Before I could speak, or even think coherently for myself, the splitting away had ended and I was again safe in the arms of my master...

The panic that possessed me washed away; I was again filled with an unworried sense of well being...

"What are you?"
"We are the people... We have studied you and we know your ways... We come," I went on, "to bring you peace.. and contentment-and the joy of-of surrender." I hesitated again; "surrender" was not the right word. I struggled with it the way one struggles with a poorly grasped foreign language.
"The joy," I repeated, "-the joy of . . .nirvana." That was it; the word fitted. I felt like a dog being patted for fetching a stick; I wriggled with pleasure.

Still not sure that parasites can manipulate the behavior of host organisms? Consider these other cases:

  • The lancet fluke Dicrocoelium dendriticum forces its ant host to attach to the tips of grass blades, the easier to be eaten. The fluke needs to get into the gut of a grazing animal to complete its life cycle.
  • The fluke Euhaplorchis californiensis causes fish to shimmy and jump so wading birds will grab them and eat them, for the same reason.
  • Hairworms, which live inside grasshoppers, sabotage the grasshopper's central nervous system, forcing them to jump into pools of water, drowning themselves. Hairworms then swim away from their hapless hosts to continue their life cycle.

Not all science-fictional parasites are harmful; read about the Crosswell tapeworm from Brian Aldiss' 1969 story Super-Toys Last All Summer Long, which keeps people who overeat from becoming obese. Not to mention robots based on parasites. Read press release on evidence for link between Toxoplasma and schizophrenia, Suicidal grasshoppers. Story via blogger Carl Zimmer and his readers.

Scroll down for more stories in the same category. (Story submitted 2/7/2006)

Follow this kind of news @Technovelgy.

| Email | RSS | Blog It | Stumble | | Digg | Reddit |

Would you like to contribute a story tip? It's easy:
Get the URL of the story, and the related sf author, and add it here.

Comment/Join discussion ( 45 )

Related News Stories - (" Medical ")

Tech Tats Prototype Sfnal Devices
'...Permanently fixed in the centre of his forehead.' -

Surgically Implantable Artificial Kidney Starts Testing
'George Walt... proved the workability of wholly mechanical organs...' - Philip K. Dick, 1964.

Computer Predicts Psychosis Better Than Psychiatrists
'The mechanism which was the portable extension of Dr. Smile...' - Philip K. Dick, 1965.

Lab-Grown Kidneys Implanted Successfully - In Animals
'For a while your colonists will have to come up to the Hospital to get treatment with the ramrobot symbiots'- Larry Niven, 1968.



Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.






Current News

Blue Origin Reusable Rocket's Vertical Landing
We're getting there, one launch at a time.

X125 Snake-Arm Inspection Robot Video
'... long, flexible, glittering tentacles...'

Super-Thin Smart Glazing Displays
'...a wide sheet of clear material suddenly flared with light and swirling color.'

Have Scientists Found A Parallel Universe Leaking Into Ours
'Ellis had found a weak point, a shimmer, at which another continuum completely had been visible.'

Active Wellness Smart Car Seat
'Maybe the car was right...'

Tech Tats Prototype Sfnal Devices
'...Permanently fixed in the centre of his forehead.'

ANNABELL AI Can Learn English From Scratch
'...Could understand not only classic programming but also Loglan and English..."

Tesla Suit Gives Haptic Hugs
'Then a pressure on the lips...'

Surgically Implantable Artificial Kidney Starts Testing
'George Walt... proved the workability of wholly mechanical organs...'

Self-Filling Water Bottle Is Beetle-Based
'That moisture trickles down...'

Senate Passes Space Mining Legislation
'The law of filing on newly discovered asteroids was definite...'

Microsoft's Surface Book Is Part Clipboard
'Floyd sometimes wondered if the Newspad, and the fantastic technology behind it, was the last word in man's quest for perfect communications...'

Police Use Predictive Maps ala 'Minority Report' Routinely
'...the data-receptors, and the computing mechanisms that studied and restructured the incoming material.'

Tesla Autopilot Road Trip 2995 Miles, 57 Hours
'The beautiful old car cruised ... under the guidance of its automatic controls...'

The 'Marching Mountains' Of Pluto
Calling Captain Future!

Graphene Thermopile May Grant Predator Heat Vision To Humans
'What the hell are you?'

More SF in the News Stories

More Beyond Technovelgy science news stories

Home | Glossary | Invention Timeline | Category | New | Contact Us | FAQ | Advertise | - where science meets fiction™

Copyright© Technovelgy LLC; all rights reserved.