Can Hookworms Cure Hayfever?

Maybe. But we need to learn a lot more about them before they hit pharmacy shelves

Evidence (some anecdotal and some clinical) suggests that hookworms could suppress the immune response in people with allergies and other inflammatory diseases. CDC

British parasitologist Jonathan Turton swallowed a hookworm. The worm made itself at home in his bowels for two years. Turton suffered from allergies, but for those two years, his hay fever disappeared. He published an account of his experience in The Lancet in 1976.

In a post for the blog Your Wild Life, Rob Dunn, a biologist at North Carolina State University, notes that some scientists think Turton might have been onto something. Dunn points to a recent review article by researchers from Duke Medical Center and the University of Central Arkansas. The researchers argue that infections with parasites like the hookworm could hold cures for not only hay fever but other inflammatory diseases as well.

Around the same time of Turton’s hookworm infection, he and his colleagues published observations about tapeworms, a parasitic relative of hookworms, gleaned through self-infection. “Turton thought that by inoculating himself with a hookworm that the hookworm would live in his gut and produce immunosuppressive compounds which would, in turn, suppress his immune system enough to resolve his allergies,” Dunn writes. 

Until around 10 years ago, most treatment involving helminthes or parasitic worms occurred on the fringes of science and sometimes outside the law—through traditional healers and slightly sketchy Internet retailers. Yet all that time, slowly but surely, science has delved further into the worm’s biology. Clinical trials of worm treatments in patients with Crohn’s disease, inflammatory bowel disease and Multiple Sclerosis produced promising results.

Given the successes of helminth treatments in traditional trials, Bill Parker, one of the co-authors on the review paper, wanted to see what untapped insights lay in contemporary unregulated self-infections, like that undertaken by Turton. Parker and his colleagues interviewed worm providers, scoured public information resources about worms and surveyed people treating themselves with worms. What they found was highly varied. Dunn explains:

For one, these treatments although rarely performed in a formal medical setting were often performed with the consent (at least tacit) of doctors in the U.S., which is to say both doctors and patients recognized the inability of existing treatments to deal with the range of problems being considered and the potential of worm treatments.  As evidence of this potential, the anecdotes collected by Parker and colleagues seem to support what has been shown experimentally in mice and rats and, in those few, precious, clinical trials in humans. Most of those who were self-treated with worms reported better treatment of Crohn’s disease and Inflammatory Bowel Disease than is seen with traditional treatment.  Remission of allergies and asthma was also common.

Before you run out to buy a hookworm to treat your hay fever, it’s important to note that these results are more guidelines for research than and that the results of the review “come with caveats,” as Dunn notes. Some patients might not see the same success, depending on the dose (How many hookworms should you take?) and follow-up protocol (How do you keep the infection under control? This a serious ailment in some parts of the world). What the researchers could also be seeing is a simple placebo effect. It’s impossible to know at this point. Before doctors start dolling out prescriptions for hookworms, we still need to learn a little more about them.

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