September 4th, 2008

The Librarian


Have been reading the fascinating Parasite Rex, by Carl Zimmer ... a book that goes into great and meaty graphic detail about critters that live off other critters (I love it, but not recommended for the easily influenced/hypochondria-prone .... you'll be trying to crawl out of your own skins just because you felt your muscles twitch). The book contains much, not only about life cycles, but about what we've learned about parasitic influences on reproduction, evolution, host control, etc., including what happens if a parasite accidentally ends up in an incorrect host. And the real attention getter so far is Toxoplasma, a protozoan that normally cycles between cats and rats, and has the chemical ability to change rat behaviour so that it's more likely to get nailed and eaten by a cat. But sometimes it ends up in a human:

"By turning rats into rodent kamikazes, Toxoplasma probably increases its chances of getting into cats. If it makes the mistake of getting into a human instead of a rat, it has little hope of making that journey, but there's some evidence that it still tries to manipulate its host. Psychologists have found that Toxoplasma changes the personality of its human hosts, bringing different shifts to men and women. Men become less willing to submit to the moral standards of a community, less worried about being punished for breaking society's rules, more distrustful of other people. Women become more outgoing and warmhearted. Both changes seem to break down the fear that might keep a host out of danger. They're hardly enough to make people throw themselves at lions, but they're a very personal reminder of hte ways in which parasites try to take control of their destiny."

Reading this paragraph and contemplating the behaviour of my species these days, I can't help but wonder if mebbe we should be systematically screening for this thing and maybe researching a repellent? Yes, I know the world is more complicated than that, but still ... according to the book, up to 1/3 of humans on the planet are infested, including virtually everyone in Europe. I have this sudden urge to start spraypainting "People don't cause wars and vandalism and teen pregnancy booms and general shitty/unsafe behaviours, Toxoplasmas do!" on walls. But that might just be my inner protozoan talking ... ;p

P.S. As I start a new chapter in the book, I discover good news (well, sorta) for my buddies suffering from allergies to pollen, animal dander, etc. ... apparently this is a side effect of having a body that naturally produces a high-than-everage amount of parasite-fighting antibodies. When you snuffle and sneeze and eye-water, you can take pride in the fact that you are also capable of taking on and triumphing over any worm, fluke or other such thing that even tries to set foot (tentacle? cilia? sucker?) inside you.