Scientists believe that the itch, and the accompanying scratch reflex, evolved in order to protect us from insects and clinging plant toxins—from such dangers as malaria, yellow fever, and dengue, transmitted by mosquitoes; from tularemia, river blindness, and sleeping sickness, transmitted by flies; from typhus-bearing lice, plague-bearing fleas, and poisonous spiders. The theory goes a long way toward explaining why itch is so exquisitely tuned. You can spend all day without noticing the feel of your shirt collar on your neck, and yet a single stray thread poking out, or a louse's fine legs brushing by, can set you scratching furiously.-- from The Itch by Atul Gawande.
25 June 2008
The itch monster
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In 2004, David Pritchard applied a dressing to his arm that was crawling with pin-size hookworm larvae, like maggots on the surface of meat. He left the wrap on for several days to make sure that the squirming freeloaders would infiltrate his system.
“The itch when they cross through your skin is indescribable,” he said. “My wife was a bit nervous about the whole thing.”
-- from a article by Elizabeth Svoboda in the NYT, 1 July.
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