The revival of maggot therapy

Maneka Sanjay Gandhi


As more and more people become antibiotics-resistant, their survival chances, if they have chronic wounds, decrease. Surgeons have now gone back to a thousand year old technique of healing called maggot therapy or biosurgery. Here, live, germ-free maggots are introduced into non-healing skin and soft tissue wounds in order to clean out the dead skin and stimulate healing.

The most often used flies in this therapy are the Green Bottle Fly (Lucilia sericata), and Northern Blowfly (Protophormia terraenovae).

Maggots are applied to the wound at a dose of 5–10 larvae per square centimeter of wound surface area, and are left within their dressing for 48–72 hours. Doctors have found that large numbers of maggots consume necrotic tissue far more precisely than surgeons can operate, and can remove foreign material and damaged tissue in a day or two. They secrete enzymes that liquefy the necrotic tissue which they eat.

Larvae kill bacteria in wounds by producing natural antibiotic like agents and growth promoting agents which cause a wound to heal rapidly. There is evidence that they secrete chemicals with a broad spectrum bactericidal effect. They also secrete ammonia, causing wounds to become more alkaline, which inhibits bacterial growth. Studies have shown that maggots destroy a wide range of pathogenic bacteria including methicillin-resistant Staphylococcus aureus (MRSA), gram positive aerobic and anaerobic strains, Streptococcus pyogenes and S pneumoniae. Once the bacteria are out, the wound is stimulated to grow healthy tissue. They are particularly useful in chronic ulcers including diabetic foot ulcers, osteomyelitis, postsurgical wound infections, and burns. Life threatening ear bone infections, and gangrene have also been treated with maggot therapy after unsuccessful antibiotic and surgical treatments. Research is on to see whether maggots can be used to eat away tumours or cancerous lesions when surgical intervention is not possible.

Evidence exists that larvae have been used for thousands of years by ancient cultures like the aboriginal Ngemba tribe of Australia, the Hill people of Myanmar, and the Mayan healers of Central America. The Mayans soaked dressings in cattle blood, and exposed them to the sun before applying them to lesions, in order to attract flies.

The French surgeon, Ambroise Pare (1510–1590), was the first doctor to note the beneficial effect of fly larvae for wounds. Napoleon’s surgeon, Baron Dominique Jean Larrey (1766–1842), who treated the injured in Napoleon’s army, observed that maggots of the ‘blue fly’ only removed dead tissue and had a positive effect on the remaining healthy tissue.

The first officially documented application of maggots was done by John Forney Zacharias (1837–1901), a Maryland-based surgeon during the American Civil War. He wrote “During my service in the hospital at Danville, Virginia, I first used maggots to remove the decayed tissue in hospital gangrene and with eminent satisfaction. In a single day, they would clean a wound much better than any agents we had at our command. I used them afterwards at various places. I am sure I saved many lives by their use, escaped septicaemia, and had rapid recoveries.”

But popular medical belief was that maggots were dirty and full of infection. By the end of the 19th century, there were hardly any doctors who supported the use of fly larvae.

During World War I, mortality from open wounds increased to 70 per cent. Antiseptic tools did not work. In 1917, William Baer, a military surgeon in France, reported his treatment of open fractures and stomach wounds with maggots. After the war, he became Professor of Orthopaedic Surgery at the Johns Hopkins University and uptil his death continued experiments with maggots on patients where all other treatment failed. In 1931, he published the first scientific study of maggots’ effectiveness in wound care.

In order to overcome the disgust of patients and staff, he created special bandages to hide the larvae, and he and his colleagues developed specific flies, and different methods, to sterilise eggs.

In the 30s and 40s, maggot therapy boomed with more than 1,000 American, Canadian, and European hospitals introducing it.

Then penicillin and antibiotics came in and the medical world abandoned maggot therapy. By the 50s, it was over.

By the end of the 1980s, millions of people were resistant to penicillin and antibiotics, pressure ulcers and diabetic foot ulcers were on the rise, and conventional wound care was inadequate. Diabetic foot ulcers alone affect 15 per cent of the diabetes population and account for over 1.5 million foot ulcers and at least 70,000 amputations annually.

In 1989, University of California physicians Ronald Sherman and Edward Pechter reintroduced maggot therapy for patients whose wounds failed to respond to antibiotics and with victims of flesh-eating bacteria. Their results were spectacular. They demonstrated that maggot-treated patients required fewer days of antibiotics and healed their wounds an average of 4 weeks faster than control patients. Studies have consistently shown that pre-amputation maggot therapy saves 40–50 per cent of limbs, usually with complete wound healing.

In the UK, surgeons John Church and Stephen Thomas set up the Biosurgical Research Unit (South Wales). Since 1995, the unit has commercially distributed sterile larvae. Thomas has calculated that the using maggot therapy for just 30 per cent of non-healing diabetic ulcers could save the United Kingdom approximately £50 million annually.

Since 1996, an annual world meeting on larval therapy, called the International Conference on Biotherapy, is organised by the International Biotherapy Society.

In 2004, the FDA cleared maggots for use as a medical device in the United States for the purpose of treatment of non-healing necrotic skin and soft tissue wounds, ulcers, and non-healing traumatic or post-surgical wounds.

Now it has become standard treatment all over the world. The revival in maggot therapy is due to technological advancements. The three most common objections to maggot therapy, during the 1930s, were the hassle of making dressings, the difficulty in obtaining live, germ-free maggots, and their high cost. Now, improved adhesives and synthetic fabrics allow doctors to make dressings to hold the maggots within the wound bed. The establishment of laboratories throughout the world, and overnight courier services, has made germ free medicinal maggots readily available. And treatment by maggots is less expensive than surgery

The UK government is spending $250,000 (Pound 196,000) in 2019 to buy green bottle blowfly maggots to send to war zones in Syria, Yemen, and South Sudan.

By 2021 doctors plan to create a do-it-yourself maggot starter kit, so that remote communities can raise them themselves.