Flesh-eating maggots and blood-sucking leeches might be considered more medieval than modern, but if you want a wound treated with maximum efficiency, few therapies can compete with 200 million years of evolution.

A study by a team of British scientists, published today, lends support to the use of the maggot in high-tech healthcare. They found that, left to graze on the skin, maggots can clean wounds that fail to heal five times faster than conventional treatments.

In a trial to investigate the clinical effectiveness of maggots for wound treatment, the leg ulcers of patients treated with larvae were found to heal just as quickly as the water-based gel normally used. The study also showed that the process of debridement — the removal of dead tissue, in this case eaten by the maggots — occurred far faster, suggesting that larvae could be used to clean sites at high speed before urgent surgery, such as skin grafts.

Leeches have also been shown to be a highly effective tool in microsurgery. The excess blood that builds up when an appendage is reattached — because of the inability to link all the broken veins — is drained off with leeches, which can consume five times their weight in a single blood-sucking.

While the Medicines and Healthcare products Regulatory Agency (MHRA) has yet to issue licences for the medical use of maggots and leeches, the US Food and Drug Administration passed both invertebrates for use in 2005.

Britain’s biggest leech and maggot providers, both based in South Wales, have experienced an increase in interest in recent years. At Biopharm, the leech specialist, annual sales have doubled to more than 70,000 of the animals in the past 15 years.

Professor Nicky Cullum, a specialist in wound care, who led the maggot therapy study published in today’s British Medical Journal, said that maggots had cleaned wounds in 14 days — compared with 72 days with gel treatment. She said there was anecdotal evidence of increasing maggot use in the NHS.

The trial, which received health service funding, involved 267 participants who had at least one diseased vein leg ulcer — common in the elderly and those who have suffered deep vein thrombosis. Participants were randomised to receive loose larvae, bagged larvae — where the maggots are placed on the skin inside a gauze bag — or gel during the debridement, followed by standard treatment.

Carl Peters-Bond, the assistant manager at Biopharm, said that he was not surprised at increased interest in the use of maggots, having seen his leech business grow steadily in recent years. “These are creatures that have evolved over millions of years to remove blood or tissue — to do a job.

Nature's nurses

Maggot (such as Lucilia sericata) Use of maggots for wound healing has been linked to Maya Indians and Aboriginal tribes, as well as during the Renaissance. Military physicians, including Napoleon’s surgeon-general, observed that soldiers whose wounds had become colonised with maggots experienced significantly less morbidity than other wounded soldiers. Maggots were popular into the 1900s, but went out of vogue with the rise of antibiotics

Leech (such as Hirudo medicinalis) Medical use was first recorded in 200BC, while George Washington is said to have died when too much blood was drained during an illness. The leech is a segmented worm related to the earthworm. The front suction cup has three sharp jaws, each with 125 teeth, that make a Y-shaped bite — leaving a mark compared to the badge of a Mercedes-Benz.

The leech can feed for six hours or more, enough to last it for as long as two years. Leech saliva contains chemicals that prevent clotting, so a wound might bleed for hours after the leech is removed

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