London School of Hygiene & Tropical Medicine

Science has a long history of self-experimentation. In the 17^th century, Sir Isaac Newton nearly blinded himself by staring at the sun for too long in a mirror to study the after-images it left on his retinas, and there are numerous other examples of people using their own bodies to further knowledge. Nowadays the practice is much rarer, with ethical considerations and large-scale trials aimed at achieving statistically significant results dominating the approach. But even today a few brave scientists occasionally volunteer to be a test subject in the name of science. One such experiment recently took place in a laboratory at the London School of Hygiene & Tropical Medicine, when medical entomology researcher and lecturer Dr James Logan agreed to infect himself with hookworm in his debut as tropical diseases expert for the TV show Embarrassing Bodies.

The aims of the experiment were two-fold: to learn more about the mechanisms by which hookworms enter the body and to test a phenomenon reported in other studies that infection can reduce some allergic responses.

Designed with the help of Dr Quentin Bickle, Reader in Parasite Immunology at LSHTM, the experiment represented a world first. State-of-the-art imaging cameras captured the exact moment the hookworm entered Dr Logan’s skin, enabling the team to watch as the creatures made their way into his arm. Over the next two months the parasites travelled through his bloodstream, reached his heart and moved into his lungs. From there, they were coughed into his throat and unconsciously swallowed, ending up in his intestine. The hookworms matured into adults, and both the worms and visible damage to the intestines were recorded when Dr Logan swallowed a pill camera. In addition to intestinal inflammation, tests revealed he had an increase in eosinophils, a type of white blood cell and a classic sign of immune responses to worms.  Although Dr Logan suffered intestinal pain, he did experience a welcome benefit as his yeast intolerance was alleviated and he was able to eat bread for the first time in years without feeling ill. Finally, all observations done, he removed his “guests” after 60 days using the anti-worming drug albendazole.

Dr Logan said: “Surprisingly, worm infections have been reported to have a potentially beneficial effect on health. For example, there are several reports of intestinal worm infection alleviating symptoms of inflammatory bowel disease, allergy and food intolerance. The worms release substances which can change the immune system to prevent your body from over reacting to the things that cause allergies in the first place.

“This is a fascinating area of research for scientists who are studying this phenomenon to try and understand how the worms are able to regulate our immune system and to discover new ways to treat autoimmune diseases.”

Dr Bickle said: “The application of novel imaging methods in the television experiment provided an interesting opportunity to find out more about hookworm skin penetration and about the balance and the link between the pathological effects of hookworm infections on the gut mucosa and the potentially beneficial effects of the modulated  immune response induced. Further research on worm infections should shed light on these immunomodulatory mechanisms, information which may lead to development of new therapies."

Disclaimer: Do not try this at home!

The new series of Embarrassing Bodies starts on Monday 5 March at 9pm on Channel 4. 

For more information go to http://www.channel4.com/info/press/press-packs/embarrassing-bodies-press-pack

(Image: Dr James Logan and colleagues watch the hookworm on screen. Credit: Maverick Television)