Maggots make a comeback

W hen a jar of wriggling maggots was presented to James Nelsonby doctors at Bridgend General Hospital, Mid Glamorgan, as a possible cure for his infected third toe, he could do nothing but nod in acquiescence. A course of antibiotics and a wound dressing had so far failed to make progress and the infection was spreading. Partial or total amputation of the toe was the only other option.

Ten days later about 100 larvae were duly applied directly on to the wound. Mr Nelson, a 53-year-old retired policeman from south Wales, expressed his surprise at how small the maggots were and was pleased that he was unable to feel them moving about on his skin. Two days later the dressing was removed, the wound much improved. Most of the dead tissue had been removed, revealing a deep cavity. A swab failed to find any evidence of micro-organisms even though antibiotic therapy had been discontinued before the larvae were applied. A small number of fresh larvae was applied and the foot was redressed. Three days later it was fully healed and Mr Nelson (not his real name) was discharged.

The use of greenbottle maggots to heal infected wounds has long been recognised. Used during the American Civil War and the First World War, they were commercially produced in the United States for the express purpose of healing wounds naturally up to the Thirties, when the arrival of antibiotics took over.

Today, larval therapy is set to make a comeback. A dozen cases have already been successfully treated at Britain's first biosurgical research unit, opened late last year by Dr Stephen Thomas, director of the Surgical Materials Testing Laboratory, Bridgend, in conjunction with the consultant orthopaedic surgeon Mr John Church.

Two other hospitals, the Churchill Hospital, Headington, Oxford, and Southlands Hospital, Shoreham, West Sussex, are already using the unit's maggots to treat patients. And clinical trials starting this month are set to confirm an already favourable prognosis. An estimated 2,000 patients a week nationally could be suitable for treatment by the maggots, says Dr Thomas.

Patients' fear that their bodies may become riddled with maggots is quite unfounded: the life-cycle of the larvae dictates they must leave the wound to pupate before becoming an adult insect, after they have gorged themselves and reached maturity. Once on the surface of the wound, they are easily removed.

However, many patients, and indeed some clinicians, find the presence of maggots in a wound unacceptable. At Bridgend, one patient has already refused treatment and others have expressed surprise. Yet the maggots often produced quicker results than conventional treatment and without the foul odour that accompanies removing dead tissue from wounds.

A row of plastic cases containing the greenbottles is kept in a "fly room" within the unit. The flies are fed liver, on which they lay eggs. The eggs are picked off and, in a separate room, are processed and sterilised. The unit produces 4,000 maggots a day.

Sterilised eggs have successfully been reared through to bacteria-free adult flies in the biosurgical unit. It is intended that a colony of these sterile flies will be established so that the eggs will be free from potentially dangerous bacteria, giving additional security to the subsequent egg sterilisation process.

Maggot magic hasn't always been trouble free. Spread over the wound, the larvae's enzymes break down and ingest tissue. In one early case, too many maggots were applied to the patient's wound and the surrounding healthy skin was damaged.

A bandaging method has since been developed at Bridgend that protects the surrounding healthy skin, prevents the patient feeling the maggots moving around and keeps the larvae in place

Research has shown that an injured fingertip may need as few as five or six maggots while a deep leg wound may require 500 to 600. The maggots are generally removed after three days.

The use of larval therapy is set to increase, says Dr Thomas, as certain bacteria become increasingly resistant to antibiotics. "I am not saying the use of larval therapy is the cure-all in every case," he says, "but I believe it will be an important weapon in the fight against wound infection. After years of turning to drugs, we are increasingly going back to natural treatments that would once have been commonplace."