Whoa, I think this is hitting the problem from the wrong end. There are people who presumably don't have worms or other parasites and don't have asthma or allergies either. Maybe we should study these people? In other words, instead of trying to figure out the cure, why not figure out the prevention?

This is a classic example of the evolutionary medicine (google Nesse and Hamilton for information on ev. med.).

By the way -and since your question is not really a question, my answer is not really an answer ;-) - check out this talk by Robert Sapolsky on the influence of parasites and our health:

http://www.edge.org/3rd_culture/sapolsky09/sapolsky09_index.html

ahha so like most gut bacteria, they have symbiotic attributes? Interesting but I suppose it would make sense as for most of evolution there was nothing you could do about them once you get them, and its in the worms best interest we live as long as possible. Though I'm sure there are some that are still bad news, or are bad news in large enough amounts (anyone remember the mail order weight loss stuff from the 1900's where you could order a tapeworm from a catalog?)

Radiolab had a great story about using hookworms to cure asthma and allergies.

http://www.wnyc.org/shows/radiolab/episodes/2009/09/25

Looks like the man in the story, Jasper Lawrence, has got a new gig related to this:

http://autoimmunetherapies.com/helminthic_therapy_about.html

I have always been a believer that all of our antibiotics and antimicrobial soaps are a problem. We now have antibiotic resistant germs, like tuberculosis, that are caused by overuse of antibiotics. I don't know that eliminating parasites has damaged our immune systems, though. All bacteria, and the like, beneficial or not, can cause infection if not kept in check. If you get a scratch in your intestine the beneficial gut fauna turns into a major infection.