From New Scientist:
In the mid-1970s, while working at the UK’s Medical Research Council Laboratories in Surrey, he [John Turton] intentionally infected himself with hookworms in an attempt to relieve his chronic hay fever. It worked. For two summers while he harboured the parasites, his allergy abated, only to return when he was free of them (The Lancet, vol 308, p 686).
Here’s what that means:
Hookworm larvae […] enter through the skin and make their way through the bloodstream to the lungs, where they pass through the thin-walled blood vessels. They then travel up from the lungs into the trachea, only to be coughed up and swallowed, allowing them to reach the small intestine where they develop into adult worms. “The potential protective effects of hookworm infections on asthma may be related to these parasites’ lung migration phase,” Flohr says.
Worms suppress the immune system, which could have adverse effects in the long run.
Not all worm infections are the same. Read the whole story to find out which disgusting parasite is right for you.
[H/T: Seth Roberts]