Exposure to Worm Infection in the Womb May Protect Against Eczema, Study Suggests (http://www.sciencedaily.com/releases/2011/01/110128095035.htm)
QuoteScienceDaily (Jan. 28, 2011) â€" Exposure to worm infections in the womb may protect a newborn infant from developing eczema, a study funded by the Wellcome Trust suggests. A large trial in Uganda showed that treating a pregnant woman for worm infections increased her child's chances of developing the allergic skin disease.
This reminds me of a BBC Horizon programme from quite a few years ago where a scientist who suffered badly from eczema who infected himself with intestinal worms and his eczema cleared up. He got rid of the worms and it came back. Reinfection cleared it up again. The treatment has been used in extreme cases. It would appear we simply have not evolved in a parasite free environment.
I have heard about hook worms being useful for asthma.
http://www.abc.net.au/rn/latenightlive/ ... 883972.htm (http://www.abc.net.au/rn/latenightlive/stories/2010/2883972.htm)