Medical Discovery News
By Drs. David Niesel and Norbert Herzog
Maggots are slimy, squirmy little creatures that make their home in dead and decaying flesh. As such, they are commonly featured in zombie movies and forensics TV shows. But maggots aren’t just a staple in science fiction. For thousands of years healers relied on maggots to cleanse their patients’ serious wounds, and the therapy is resurging as a modern medical tool.
The ancient Mayans began using maggots, which are the larvae of fly species, to disinfect wounds because maggots efficiently consume decaying flesh without affecting healthy tissue. Today, an average application of sterile or bacteria-free maggots can consume 10 to 15 grams of dead tissue per day.
Doctors began returning to maggot therapy in the last 20 years when certain bacterial infections stopped responding to antibiotics. Maggots secrete proteases, which are enzymes that liquefy dead tissue. When they ingest the tissue, they consume any infecting bacteria, which are then destroyed during the larvae’s digestion. But the maggot secretion itself has healing properties that lower inflammation and prevent the growth of bacteria, both of which scientists had no explanation for until a recent study.
A team led by surgical resident Gwendolyn Cazander of Leiden University Medical Center in the Netherlands may have figured out how maggots promote healing. They took blood samples from people whose wounds were treated with maggots and those without maggot therapy. After measuring blood samples for proteins involved in inflammation, they found two complement proteins, C3 and C4, decreased up to 99.9 percent in samples from those with maggot treatment. Only pieces of the complement proteins were left in wounds where maggots had secreted their special enzymes.
Maggot secretions are tough – even after sitting on a shelf for a month and being boiled, they still reduced the levels of inflammatory proteins. It makes sense that maggots have developed the ability to reduce the host’s inflammatory response in order to prevent an attack on them by the immune system while they infest a wound.
Researchers still don’t know what exactly in maggot secretions reduces inflammation and they’re working to identify that now. Most likely, it’s a variety of mechanisms that make this once archaic therapy a valuable clinical tool. Maggots are now ideal for wounds that get little to no blood flow, or tissue in the process of regenerating. In these cases, antibiotics cannot be carried to the site by blood, which increases the risk of infection. Maggots are also ideal when serious infection has set in such as gangrene and foot infections in diabetics.
At times, they’re even better than surgeons in eliminating all traces of an infection, which can be difficult to spot. No wonder maggot therapy has been given a fancy, more appealing name: biosurgery.
Medical Discovery News is a weekly radio and print broadcast highlighting medical and scientific breakthroughs hosted by professor emeritus, Norbert Herzog, and professor, David Niesel, biomedical scientists at the University of Texas Medical Branch at Galveston. Learn more at www.medicaldiscoverynews.com.