Allergy Treatment: A Healthy Dose of Hookworms?

How far are you willing to go to treat your allergy and asthma problems?

Would you allow your doctor to infect you with parasitic worms in order to suppress your allergy immune system? Apparently there are allergy sufferers who would.

A physician/scientist conducted a study that involved the intentional infection of 15 allergy patients with hookworms. Another 15 were part of the control group (allergy patients in the study that were not infected for the study). The infected patients had marked reduction of allergy symptoms compared to the control group.

A New York Times article reported that Dr. David Pritchard, an immunologist-biologist at the University of Nottingham, while doing field work in Papua New Guinea, noticed that Papuans infected with the hookworm Necatur americanus, had fewer allergy symptoms, asthma, and other immune-related problems.

Dr. Pritchard was so confident about the safety of experimental infection with hookworms that he infected himself with several of them to prove his point. Although he admitted to some abdominal pain and diarrhea, he concluded that by using only 10 worms instead of 50 (the number he used on himself) for infection, side effects could be minimized. He subsequently gained approval from a British ethics committee to launch his first study (referred to above).

You must be wondering at this point: What are Hookworms?

There are two major species of hookworms that infect humans. Necatur americanus is found in North and South America, Central Africa, Indonesia, islands of the South Pacific and parts of India. Ancylostoma duodenale causes infections in Mediterranean countries, Iran, India, Pakistan and the Far East.

Necatur americanus is the hookworm prevalent in New Guinea and studied by Dr. Pritchard. This parasite is found in areas of poor sanitation where human feces contaminate the soil. The soil must be moist in order to maintain the larvae of the hookworm. This is why the tropics and subtropics are the primary areas where hookworms are found.  The hookworm Necator americanus gains access to humans by penetrating the skin of the feet. The life cycle of the hookworm is dependent on human or animal infection.

It takes three or more hookworms to infect humans. Walking barefoot through soil containing the larvae allows for skin attachment. After getting through the skin they migrate to the lungs over 1-3 weeks. Once in the lungs, they cross through the small blood vessels to the airways where they ascend the tracheobronchial passage to the throat. They are subsequently swallowed eventually landing in the small intestines where they attach to the walls and mature. As they reside in the intestines, they suck blood and serum proteins from small blood vessels of the intestinal wall for feeding. Once the larvae mature to adults, the males fertilize a female which will lay eggs in the intestines. Eggs from the hookworm may be found in the stool about 6-8 weeks after infection.