The propensity of maggots, or blowfly larvae, to feed on necrotic tissues while leaving healthy tissues untouched, and thus remove dead and dying tissues from infected wounds, has once again attracted the attention of modern medicine. While it might make us squirm today, treating a septic wound by applying maggots was well known in the ancient world, and had become revived in the western world during the Great Depression to the point where it was the standard amputation-avoidance treatment of choice for gangrene during World War II.
Modern MDT, or maggot debridement therapy, consists of placing an air-permeable dressing of a thousand or so trapped, sterile blowfly maggots on top of the festered wound and leaving them there for a day or two while they do what comes naturally. Since these maggots have been specifically raised for this purpose, there is no possibility of the cross-infection commonly associated with buzzing flies. Two different methods of MDT currently exist. In the first, the maggots are placed directly in the wound and blocked from escaping by the dressing; while in the second, newer method, the maggots are separated from the wound and able to feed only through the dressing.
The medicinal function of the maggots has three separate parts. First, they debride, or clean, the wound. Second, both the proteolytic enzymes they produce and their consumption of septic tissue help to sterilise the wound. Finally, their activity encourages blood flow to the wound, which helps it to heal.
Apart from psychological discomfort, very few side effects have been reported, certainly on a comparable level with most pharmaceuticals. The treatment seems to cause far less pain than the wound itself. However, serious side effects do occur very rarely, and at least one death has been reported (Emsen, 2007).
Maggots also have a role to play in forensic medicine. Since the life cycles of various types of flies are known, the types of maggots and mature flies around a dead body can indicate an approximate time of death.
References:
Emsen IM. Fatal side effect of maggot treatment on wound healing. Plast Reconstr Surg 2007;119(5):1624.
