It was only in the 1940s that doctors began to deliberately and regularly employ maggot therapy. They would take the eggs of the green- bottle fly, allow them to hatch into maggots only a millimetre or so in length, and then apply the newborn maggots to the wound before bandaging it. The maggots would then feed on the dead and dying tissue, while leaving healthy tissue alone, thereby cleaning the wound and reducing the risk of infection. After a few days the bandages would be removed, along with the maggots, which would have increased in size to perhaps seven millimetres. Typically, maggots take 14 days to turn into flies, so as long as the bandages were changed regularly, there was no risk of this metamorphosis occurring in the wound.
Maggots are an effective anti-bacterial agent. Not only do they kill harmful bacteria in their gut, it seems that they also exude antibiotics and alkali chemicals, both of which help to prevent infection. But, as antibiotics such as penicillin became increasingly popular, maggot therapy seemed unnecessary and fell into disuse.
A few decades later, maggot therapy is back in fashion, thanks to more accidental infestations of wounds. For example, a car crash victim spent three days lying in a ditch and his wounds became infested with maggots. When he was eventually rescued surgeons were surprised to see the wound in such good condition. Prompted by this and other similar events, doctors have now set up more than 450 centres in Britain which offer maggot therapy to help in the treatment of leg ulcers, pressure sores and other wounds. Maggots are not yet available on prescription.
Part of the reason for the maggot's new-found popularity is that, while bacteria have evolved and become resistant to many traditional antibiotics, it remains a potent anti-bacterial force. Most recently, and most importantly, the Surgical Materials Testing Lab at the Princess of Wales Hospital, Bridgend, has found evidence that maggot therapy can combat methicillin- resistant Staphylococcus aureus (MRSA), the so-called superbug, which seems to be resistant to virtually all known antibiotics. If this research turns out to be correct, then it is likely that maggot therapy will become even more popular.