If the thought of parasitic hookworms burrowing through your skin until they find your intestine makes you nauseous, spare a thought for people who experience coeliac disease. This genetically predisposed condition affects one in 70 people in Australia, causing damage to the small bowel as a result of the immune system reacting abnormally to gluten.
But there may be hopes for a treatment, with the continuation of a bold experimental trial by Australian researchers. Forty patients will be injected with hookworm larvae in a follow-up to an earlier study that suggested the parasites are effective in treating coeliac disease.
"Symptoms of coeliac disease vary, with the most common being gastrointestinal upsets," said John Croese, an adjunct professor at James Cook University (JCU) and a gastroentologist at The Prince Charles Hospital in Brisbane. "Others symptoms, some more severe, may include fatigue, anaemia, unexplained weight loss or gain, bone or joint pains and swelling of the mouth or tongue."
There's currently no cure or effective treatment for coeliac disease – other than avoiding gluten entirely – but some of these symptoms appear to be mitigated in patients who host hookworms, and scientists have been trying to work out whether the parasites could be part of an effective treatment.
In the previous study, gluten-intolerant participants were infected with 20 hookworm (Necator americanus) larvae. During the course of the research, the infected participants were given gradually increasing doses of gluten, starting with only one-tenth of a gram daily and progressing incrementally to 3 grams, at which point they could eat their way through a medium-sized bowl of spaghetti – a serving that would have previously induced diarrhoea, cramps and vomiting.
Thanks to the presence of the hookworms, which researchers believe secrete a protein that has anti-inflammatory properties, the discomfort and illness that gluten usually causes for coeliacs was reduced – and the new study intends to ramp up the gluten intake to the point where patients are eating a regular diet (including normal levels of gluten) without any problems.
"The gut becomes more accepting of different foods," said Croese. "It's the most exciting development I am aware of in the treatment of coeliac disease."
The researchers aren't proposing hookworm larvae as a permanent solution for coeliacs – not in the long term, at least. However, until researchers are able to isolate the protein secreted by the parasites, as an interim measure hookworms will have to do.
Not that this is a problem for those who took part in the original research, it seems. They loved the beneficial effects of hosting hookworms in their bodies – and even bonded with the parasites.
"I actually went out and I went to town and I had pizza and ice-cream, and salad sandwiches and Subway, just all the things I've missed for the last 15 years. And I was absolutely fine, I was terrific," Peter Letheren, one of the patients involved with the pilot study, told the ABC.
"The worms take about four years before they die, unfortunately – and we call them our friends. Everyone in the trial called the worms our friends, so we don't want them to leave us, but they do."
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