This article was taken from the March 2015 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
Developing drug treatments in the lab and ultimately testing them in human trials is a long and expensive progress. David Pritchard takes a different route: testing his theories on himself.
The 62-year-old professor of parasite immunology at the University of Nottingham studies the ways chemicals produced by parasitic worms and insects can affect the human immune system -- by exposing himself to these organisms and seeing what happens. "I was a zoologist first and then an immunologist and now I am an entomologist," says Pritchard. "I am essentially a drugs-from-bugs person." He became interested in the link between parasites and humans in the 70s, when he came across anecdotal evidence that people in the tropics who were infected with hookworm had fewer allergic reactions, such as asthma and hay fever. It looked as though the worms were suppressing their host's immune response to avoid being rejected. "The trouble is," he says, "being infected with too many hookworms causes serious problems, such as anaemia, so we had to find a safe dose that would be enough to suppress allergies but not enough to cause health problems."
Pritchard was one of ten volunteers who applied a dressing crawling with hookworm larvae to his arm to see how many worms the body could tolerate. "I found out the hard way the upper limit is about 25 worms," he says. "More and you get cramps and diarrhoea."
Pritchard and his team identified two blood-feeding enzymes from the hookworm. These are now
being used in research at George Washington University into a vaccine against hookworm. Meanwhile, in Nottingham, he is working on ways of using the worms to alleviate the symptoms of multiple sclerosis.
And he is still exposing himself to bugs -- this time, maggots. "I'm interested in a wound-cleaning
maggot called Lucilia sericata and the immune response it causes," he says.
This article was originally published by WIRED UK
