Do worms protect us against autoimmune diseases? The epidemiological evidence is strongly suggestive. Ethiopian, Brazilian, Venezuelan, and Gambian adults have less asthma when infected with nematodes; Gabonese schoolchildren with schistosomiasis have fewer allergic reactions to dust mites than do those who are not so infected, and children living on farms in Germany have fewer allergies than children living in cities (Wilson & Maizels 2004). One of the most debilitating autoimmune diseases, multiple sclerosis, is virtually absent in Roma, Inuit, and Bantu, is rare in the indigenous peoples of the Americas and Asia, and is rare in the tropics generally. And in the developed world, (more…)