Into the Void

Speaking of the screwfly, remember the big push to eradicate the screwfly back in the 60s or 70s? This fly lays its eggs on an open sore, the maggots hatch and go through a series of instars, pupate and become flies. The flesh is further damaged by this activity, making more open sores for more flies. Screwflies can devour an infested animal in a matter of days. They also infest babies eyes, so there was a huge effort to control them. This is a fascinating story about using pheromones to exterminate a species.

Ok, since you asked… The screwfly gets its name by its mating habits. When screwflies mate, they line up head-to-tail. The female emits a pheromone that triggers the male to turn around - hence screwfly - and then they mate. To control screwflies, entomologists came up with a chemical that interfered with the female’s chemical message. Instead of turning around, the male happily mated with her head. Sounds like some guys I’ve known.

This sort of thing was the basis of an interesting sci-fi story in which aliens who wanted to colonize the Earth sprayed something that brought out the aggressive component of male sexual desire and suppressed the sexual component. All of the women were killed, of course. Too bad it didn’t turn the women into human Preying Mantises instead.

Here’s a fun parasite: the Guinea worm. These 3-foot-long parasites have been with us for so long that some Egyptian mummies have them. They feed only upon humans.

You get guinea worms by drinking contaminated water. The worms then chew their way out and orient themselves so that their genitals dangle outside the flesh, usually the flesh of the foot, but they can really show up in any part of the body. The lesion burns like mad, so sufferers douse it with cold water to ease the pain. In the parts of the world where the Guinea worm is found, the sufferers recontaminate the water supply.

So now you have a three-foot long worm embedded in your body. The locals used to burn the exposed parts with cigarettes to try to kill the worm. Unfortunately, this often resulted in infection or even a massive allergic reaction when the three-foot long worm died. The worms are more safely removed by wrapping the exposed parts around a small stick then slowly drawing the worm out over days or weeks. The medical symbol the Rod of Asclepius may represent this procedure.

The caduceus with its two snakes is similar to the Rod of Asclepius, but is probably a symbol of wisdom rather than of medicine in particular.

The snake is a symbol of wisdom in cultures where knowledge is encouraged. In cultures where Blind Faith is enforced, the snake is Evil Incarnate. Serpent knowledge is the source of Original Sin, and it is knowledge that brings about the Fall. In this mythology, our progenitor Adam is infested with guinea worms. They can’t possibly have evolved into human parasites from something else, right?

Damn, there I go spouting heresy again. Burn the witch!

An apple a day keeps the doctor away!

I’ve been thinking about parasites.

Not the “earworm” sort of thing where you hear a bit of a song and can’t get it out of your head for the rest of the day. Not even the everyday suck-on-your-intestines nasties. I’m thinking about the kind of parasites that get into your mind and control your thoughts and actions.

For the record, I know *of* these parasites but I’m looking up the names online as I go along. Damn it, Jim, I’m an engineer not a biologist.

The sensitive and the squeamish may want to stop reading this now.

Really.

Ok, now that we’ve shaken off the fleas…

There’s a parasite that infects rodents, Toxoplasm gondii. It makes them all hyper and weird and THAT makes them easier for cats to catch. Where it gets interesting is that the life cycle of this parasite requires that it pass through the stomach and intestinal tract of… wait for it… a cat! How convenient!

I have occasionally wondered whether the active phase of the infestation makes humans more attractive to cats. Something like 40% of the population has antibodies to T. gondii. Maybe “the rat race” isn’t so far off, eh?

The psychiatrist E. Fuller Torrey - whose sister is or was schizophrenic and is probably somewhat affected himself - is promoting the paranoid delusion that cat shit causes schizophrenia. Is it possible that when his sister got sick he blamed Fluffy? This, my friends, is a major researcher into bipolar disorder at the prestigious Stanley Foundation. We are SO f*cked.

Oh. In other countries with the same rate of antibodies to T. gondii in the population, there is less schizophrenia and the prognosis is better. Personally I think schizophrenia is a product of industrialization and I wish Dr. Torrey would quit wasting valuable time digging in the cat box.

There are many other parasites that affect the behavior of the host. Three
more follow:

Sacculina infects crabs. If by “infects” you mean “castrates and takes over the mind and body.” This is the stuff of nightmares. Succulina injects itself into a crack in the exoskeleton and quickly grows out through the entire nervous system. Crabs that are infected can’t breed, can’t regenerate limbs, and spend the rest of their lives doing nothing but feeding and caring for the parasite. They even stroke and clean the monster, which in the female crab lives in the compartment where she usually holds her unhatched eggs.

Can you imagine having some THING living inside you, changing your brain so that the thing becomes the focus of your entire life? This is the stuff of nightmares.

The lancet fluke has a fairly complicated life cycle, but the interesting part is where it infects an ant. An infected ant acts like a regular ant by day, but at night she climbs up a blade of grass and waits at the top. The next stage of the parasite’s life cycle is to become a liver fluke in a cow. How better to be eaten by a cow than to have your host sit on the top of a blade of grass at dawn!

Another fluke infects fish - the young flukes migrate to the fish’s brain and crowd around it like pigs at a trough. Fish who are infected periodically stop what they’re doing and flail about at the surface of the water. Shorebirds find the flailing fish easy to catch, and yep, the birds are part of the life cycle too. The parasites boost the bird population by making more food available, but the fact that they kill their fish hosts puts limits on how much of the fish population can be infested. Again, a very convenient situation.

Hopefully you all are getting where I’m going with this - that parasites can make you do things you might not have done if it didn’t benefit the parasite. A parasite that flat out ate us alive would be found and eradicated like the screwfly was. Most of them are merely a nuisance.

Humans are, for the most part, repulsed by parasites. I’m sure there are some parasites somewhere that are status symbols, but I sure can’t think of
any. Usually we want to avoid parasites if we can, and expel or exterminate them when we can’t.

It would be more adaptive if the parasite made humans enjoy being infested. I’ve read sci-fi stories about this sort of thing, and I remember at least one Star Trek episode where the infested feel **enriched** by the parasite and are absolutely delighted to forcefully spread it to others.

If you believe the writer William S. Bourroughs, language itself is a virus. Certainly memes, often called “mind viruses,” have some quality that helps them spread. Does anyone remember Laurie Anderson’s “Language is a Virus” from the “Home of the Brave” video?

Oh, he did a really nice book about the co-evolution of cats and people called “The Cat Inside” or something similar. I highly recommend it for the cat-infested.

Next section of this article will be on how *ideas* influence our thinking and behavior in the same way that parasites do.

Technorati: parasites medicine medical mind schizophreniam T+gondii cat+shit William+S+Burroughs memes