© Nicola Harris/EPFLThis helminth, seen here under fluorescent staining, infects rodents.
Intestinal worms, multicellular parasites in the helminth family, often surface in areas with poor sanitation and can cause chronic infections with debilitating side effects. These animals also communicate on a basic level with gut bacteria in order to boost the host's immune system, found a study published in the journal Immunity.
The gut's bacteria, also known as the microbiome, influence metabolism, immune function and possibly even mood, according to previous studies. Given how much of our health is affected by gut bacteria, the worms practically have a direct line the body's metabolic switchboard.
For the latest study, researchers looked at how intestinal worms affected infected pigs. By drastically altering the animals' immune systems, the worms led their hosts to produce increased levels of short-chain fatty acids, which can activate receptors that in term influence the immune system.
When the researchers looked at the immune systems of mice similarly infected with helminths, they saw the same pattern: increased production of short-chain fatty acids affecting the same receptors and in turn the immune system.
Helminths co-evolved with mammals, so they know their way around their hosts. Far from being altruistic, the worm instead helps the host as a means of protecting itself. After all, a (relatively) healthy host makes for a better food source.
Intestinal worms aren't much of a concern to people in industrialized countries, but billions of people in the developing world, mostly children, are infected with these parasites. Once inside a host, intestinal worms divert nutrients to themselves and excrete toxic waste. They cannot reproduce inside a host organism, however.
Those infected with the worms may experience a variety of symptoms, including pain, fatigue, weight loss or even dysentery. Different intestinal parasites require their own courses of treatment, ranging from a single drug dose to weeks of medication, according to the University of Maryland Medical Center.
Some of the side effects of these parasites shacking up in a person's intestines can be positive. For example, they can have an anti-inflammatory effect that can help individuals coping with inflammatory disease, such as severe allergies, Crohn's disease or asthma, or autoimmune disorders, like celiac disease. The use of parasitic worms to treat disease, known as helminthic therapy, is still experimental, but has shown some promise in animal studies.
Intestinal worms get a bad wrap because they're parasitic, toxic and just plain disgusting. But if researchers can figure out how to harness the potential benefits of these literally gut-wrenching parasites, millions of years of these worms infecting the insides of likely trillions of animal hosts could eventually just be water under the bridge, with these animals finally shaking off their slimy reputation.
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Comment: Helminthic therapy sounds like an extreme way to go about reducing inflammation and increasing short-chain fatty acid production that could be done more safely and effectively by simply adopting a ketogenic diet.