Hungry maggots crawl into modern medicine
When Andy Anderson had osteomyelitis, an acute bone infection, he spent months taking antibiotic medication intravenously. His knee wasn’t getting any better, and he felt terrible. Finally, one of his care providers suggested an altogether different approach: maggots.
“I figured I had nothing to lose,” Anderson, 63, says in a phone interview with the Straight. “The drugs would make me very sleepy. I was constantly tired and was so damn miserable.
“Thank God I got those maggots,” the Vancouver resident says. “It was absolutely incredible. They cleaned the infection right out of my knee.”
Although the thought of the creepy critters chowing down on their own limb would be enough to make some people gag, Anderson didn’t hesitate. The only thing that startled him was how fat the creatures were once they were removed.
“They were obese,” he says with a laugh. “They had a good feast on me.”
Also known as debridement therapy (debridement being the removal of dead and infected tissue), maggot therapy is remarkably effective, according to Christine Pearson, a Vancouver registered nurse and board member of the Canadian Association of Wound Care.
It works like this: maggots only go after dead tissue. They secrete an enzyme that liquefies that necrotic tissue; then they drink it up. The bacteria are killed in the maggots’ digestive tract and by an antibacterial substance they excrete. Five to 10 of them per square centimetre of wound base are placed in the affected area. Typically, maggots are applied for 48 hours and covered with—and contained by—an absorbent, breathable bandage. A patient might need anywhere from one to six applications.
“I’ve never had a patient ever refuse treatment,” Pearson says in a phone interview. She notes that it’s not a first-line therapy, so by the time it’s offered, most people have tried several other medical approaches without any benefit. “They just want to get better. Most of them have seen CSI [: Crime Scene Investigation] and are quite intrigued by it. Maggots are really good workers.”
Maggots can be used on any nonhealing wound that contains dead tissue, including pressure ulcers, venous ulcers, traumatic wounds, surgical wounds, and diabetic ulcers.
Besides being extremely effective, the centuries-old therapy is cheap. One treatment costs about $100.
But in Canada, the use of the insect larvae is also caught up in bureaucracy, Pearson explains.
Maggots used to be classified by Health Canada as a “medical device”. However, the federal department now lists them as a “drug”. As a result, they can only be imported from the U.S. through the Special Access Programme, which, according to Health Canada’s Web site, “provides access to nonmarketed drugs for practitioners treating patients with serious or life-threatening conditions when conventional therapies have failed, are unsuitable, or unavailable”.
“It’s a whole rigmarole to access maggots,” Pearson says. “You have to fill out the same forms as if you were using an experimental chemotherapy drug on someone. It’s a lot of paperwork, and it’s very onerous.
“Canada is the slowest advanced country to implement maggot therapy,” adds Pearson, who used maggots about once a month before the regulations were changed. “It’s been around forever, and it’s in use in the States, South Africa, Australia, Europe—everywhere except Canada. It’s just bizarre how that occurred.”
Once routinely used to treat wartime wound infections, maggots lost favour in the 1940s with the emergence of antibiotics. But their use has escalated in popularity over the past decade, in part because of the rise of antibiotic-resistant bacteria.
The maggots used for therapy are the Lucilia sericata species, more commonly known as green bottle or blowfly. To make maggots “medical grade”, they are produced in a sterile laboratory where the eggs are washed in an antiseptic solution, then placed on a clean food source of brewer’s yeast and soy. This keeps them alive until they can be transported to the patient in a sterile jar.
Pearson notes that the Canadian Association of Wound Care has written Health Canada to request the classification be changed back.
Furthermore, a UBC lab is considering breeding and distributing maggots throughout Canada so that people here no longer have to bring them in from California, the only place currently producing medical-grade maggots in North America.
Bringing them in from the U.S. is cumbersome in itself: to order a batch of maggots for use here, care providers must have an import permit from the Canadian Food Inspection Agency and a border broker to address any issues at customs.
The United States Food and Drug Administration has endorsed maggot therapy for treating foot ulcers, bedsores, and postsurgical wounds since 2004.
A 2009 study in the British Medical Journal found that maggots are not superior to dressings made of hydrogel, a type of polymer gel, at increasing healing rates or decreasing bacteria. However, they are better at debriding wounds.