When I volunteered several years ago as a physician in a small hospital in West Africa, one of the most frustrating and frightening diseases I saw was sleeping sickness. Now, an investigator supported by the NIH Common Fund aims to figure out how this disease pathogen manages to evade the human immune system.
Monica Mugnier’s fascination with parasites started in college when she picked up the book Parasite Rex, a riveting, firsthand account of how “sneaky” parasites can be. The next year, while studying abroad in England, Mugnier met a researcher who had studied one of the most devious of parasites—a protozoan, spread by blood-sucking tsetse flies, that causes sleeping sickness in humans and livestock across sub-Saharan Africa.
Caption: Scanning electron microscopy image of T. mu in the mouse colon. Credit: Aleksey Chudnovskiy and Miriam Merad, Icahn School of Medicine at Mount Sinai
Recently, we humans have started to pay a lot more attention to the legions of bacteria that live on and in our bodies because of research that’s shown us the many important roles they play in everything from how we efficiently metabolize food to how well we fend off disease. And, as it turns out, bacteria may not be the only interior bugs with the power to influence our biology positively—a new study suggests that an entirely different kingdom of primarily single-celled microbes, called protists, may be in on the act.
In a study published in the journal Cell, an NIH-funded research team reports that it has identified a new protozoan, called Tritrichomonas musculis (T. mu), living inside the gut of laboratory mice. That sounds bad—but actually this little wriggler was potentially providing a positive benefit to the mice. Not only did T. mu appear to boost the animals’ immune systems, it spared them from the severe intestinal infection that typically occurs after eating food contaminated with toxic Salmonella bacteria. While it’s not yet clear if protists exist that can produce similar beneficial effects in humans, there is evidence that a close relative of T. mu frequently resides in the intestines of people around the world.