From The Boston Globe: His parasite theory stirs a revolution.

"What if I told you," Joel Weinstock said, "there were countries where the doctors had never seen hay fever?"

It is another piece of evidence, another "aha" moment in the global medical mystery that Weinstock — the chief of gastroenterology and hepatology at Tufts-New England Medical Center — has narrowed down to one chief suspect: the worms.

Weinstock, 59, specializes in studying why immunological diseases – everything from hay fever and asthma to diabetes and multiple sclerosis – are on the rise in developed countries but remain relatively uncommon in undeveloped countries. He believes these diseases, many of which were almost unheard of 100 years ago, are because of changes in our environment, a lack of exposure to something. And he thinks that something may be the worms. [continue]