Yeap i've posted other simular studies before about when children are raised to play outside and in the dirt that they have less asthma and allergies when they grow older as it allows our immune system (Immunoglobulins) to recognize the parasites and allergens etc. as normal.
I also posted a story in the City Data Science Forums about people with more parasites and worms in their intestines have less autoimmune diseases as some researchers believe we have lived with these in our gut since the hunter gatherer days and so the parasites and our immune system work with each other
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8 Parasitic Worms That Live In Us