To Absent Friends

As allergies become more prevalent, worms – or their lack – are being blamed.

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Being infected with intestinal worms may not sound like an attractive proposition. Soon, however, it may be the way we treat a range of allergies and autoimmune conditions such as asthma, eczema and coeliac disease. All are on the rise in developed countries, and the helminth, or parasitic worm, is believed to hold the key to why.

“There is a theory called the absent friends hypothesis,” says Kara Filbey, a researcher at Wellington’s Malaghan Institute. “Our immune systems evolved to have worms. We’re supposed to have some inside us, but now we’ve eradicated them completely in the Western world.”

To make a home inside the gut, worms need to be able to keep a lid on our immune system so it doesn’t attack them. Without them there to control the inflammatory response, the theory is that our system starts responding to things it shouldn’t, such as allergens in the environment.

“If you look at places where they do have worms endemically, such as Africa or Southeast Asia, they have a lower rate of allergies and inflammatory disease,” says Filbey.