There has been a surge of press recently on hookworms. But the press has not been covering any sort of First World outbreak of this Third World affliction. They have made little mention of the dangers to children and pregnant women who are infected with hookworms including anemia, protein deficiency, abdominal pain, and diarrhea. Nope, instead the press is covering a recent interest in using hookworm to suppress allergies.
The idea, based on research by David Pritchard, an immunologist-biologist at the University of Nottingham, is that parasites like Necator americanus, or hookworm, that live inside other animals have to have some serious weaponry to battle the host’s immune system. One tool in their arsenal may be to release agents that simply suppress the immune response of the host. This idea occurred to Pritchard while thinking about the prevalence of allergies and other auto-immune disorders in the First World compared to the Third World. Now immunology is really not my forte, but here is my elementary-level understanding of how our immune system works: White blood cells and the histamines and antibodies they produce are terrific at attacking foreign crud in our bodies, be they viruses, bacteria, parasites, pollen, or whatever. Additionally, our immune system also has the onerous task of not only specifically identifying what they should kill, but also what they should not kill, i.e. our own tissues. Auto-immune disorders are usually an indication that there is a problem in the immune system such that the line between Self=Good, NonSelf=Bad becomes blurred and murky. For instance, alopecia areata, a type of hair-loss that is not due to male pattern baldness, is thought to occur when a person’s immune system begins to attack their own hair, obviously erroneously. The flip side is that the histamines that are produced by our immune system as it fights foreign invaders like pollen can cause the watery eyes and mucus associated with allergies.
So, get yourself infected with hookworms that pump out immune suppressants and goodbye allergies and auto-immune disorders, right? That is what Pritchard and others who have prematurely jumped on this panacea band-wagon are saying. Aside from infecting himself, I believe that Pritchard is following the normal chain of basic research and clinical trials necessary to uncovering how hookworms handle their hosts’ immune system. But others, like Jasper Lawrence who was featured on This American Life this week, are bypassing these steps. Check out his slick website that does not mention hookworms anywhere on the front page or the story of his escapades stomping barefoot through latrines in African villages until he was infected with hookworm. Oh, did I fail to mention that hookworm bores up through the soles of your feet until it settles in your gut to thrive, be pooped out, and spread to anyone who comes in contact with your pooh? Yeah, neither does he on his website.
The trick here is that Pritchard and Lawrence are probably right, an infestation of hookworm may well diminish your allergies because they are suppressing your immune response.* However, we have many, non-parasite options that do the same thing! We currently treat allergies and auto-immune disorders with drugs that suppress our immune system. Histamine blockers like Claritin and Benadryl do this, as do steroids like corticosteroids which we tend to apply as creams to rashes and such. Aside from the ick factor of worm infestation, the necessity for such a drastic and possibly dangerous treatment when we have a large variety of drugs that do the same thing utterly escapes me. (Have you already guessed from where Lawrence harvests the hookworms that he sells? Yes, his own feces.) I can only chalk it up to a sort of demented natural fallacy: infestation with parasites is more natural, and therefore better, than non-infestation with parasites.
I am not one to shy away from a conversation about poop. In fact, my dissertation is largely based on poop. So if you can make an argument for why infecting yourself with a parasite that is transmitted via feces would be a better treatment for seasonal allergies than a Benadryl and a tissue, please enlighten me.
David I. Pritchard, Doreen S. W. Hooi, Alan Brown*, Moses J. Bockarie, Rebecca Caddick, and Rupert J. Quinnell (2007). Basophil Competence during Hookworm (Necator americanus) Infection. Am. J. Trop. Med. Hyg., 77(5), pp. 860-865