Grub’s Up! The Science Of Larval Therapy



The prevalence of ‘incidental maggots’ is well documented in World War I, particularly in the case of wounded foot soldiers who, after spending weeks in the trenches, were transferred to field hospitals for treatment. Their foul-smelling dressings led surgeons to expect the worst decomposition and infection. What they found instead were perfectly clean wounds. Incidental maggots had been at work, removing the dead flesh, destroying the bacteria and promoting healing.


So, if maggots clean wounds so efficiently, why are they not the first line of medical treatment for bad wounds? Liz Morris, an advanced wound-care practitioner at WoundNet Wound Clinic in Claremont,

Cape Town, explains: ‘Firstly, surgical techniques have improved and, secondly, in 1928 Alexander Fleming discovered penicillin. This was the first antibiotic, one of the greatest inventions of all times, and the death knell for bacterial infection.’

That is, until the prevalence of antibiotic-resistant bacteria. ‘This is one of the reasons maggot therapy is making a comeback,’ Morris says, as it is particularly effective at cleaning chronic wounds, such as diabetic ulcers, in order to achieve healing.


The scientific definition of a maggot is a ‘soft-bodied, legless larva of a fly or other insect, found in decaying matter’. Medicinal maggots are really smart little critters and, contrary to what one might think, are squeaky clean.

Morris uses maggots regularly, particularly on diabetic patients, at the clinic. These maggots are farmed by Surgimaggs in Pretoria, a division of Inqaba Biotec.

The first batch originated from a Swiss laboratory and continues to be grown in a sterile environment. Dewald Swanepoel, the technical specialist for wound care at Surgimaggs, says, ‘We use the Lucilia sericata species because they are rather particular about their dining habits – they only eat dead tissue.’


According to Swanepoel, the maggots seek and eliminate dead tissue and bacteria through a triad of assault: debridement, antimicrobial activity and stimulating growth of live tissue.

Maggots actually do a remarkable job of debridement. The hundreds of little hair-like structures on their bodies turn them into mini-bottlebrushes – the minute spines scrape along the wound as the maggot wriggles, loosening dead tissue. Their secretions liquefy the dead tissue which is ingested. Each maggot is capable of removing 25mg of necrotic material from a wound within just 24 hours.

They also secrete saliva that contains deoxyribonuclease (DNase). This enzyme plays an important role not only in debridement but also in inhibiting microbial growth. Morris describes it as making ‘maggot soup’. Ingredients include the exudate or fluid from the wound, partially digested remains of dead cells, microbes, antibiotic-resistant bacteria and biofilm (the starch layer on the wound that is so difficult for antibiotics to penetrate). They slurp this up and in the process reduce oedema (swelling).


The maggots are ordered according to the size of the wound, usually 5-8 maggots per cm2. The flies in the lab are stimulated to lay eggs which are collected, disinfected and grown in an environment free of microbes. After

24 hours they reach the right size (1-2mm), after which they are packaged in a wound bag, placed within a sterile container, induced into a comatose state and transported in a cooler box to hospitals.

They are then warmed and woken up.

Although almost microscopic when they arrive, after feeding for over 72 hours they are fat and satiated at around 1.5cm. One can’t help thinking perhaps a little smug too, after they have cleaned up the wound and removed the infection by destroying harmful bacteria. They have a right to be; it’s a job very well done.

Maggots look after their own wellbeing too, by protecting themselves against infection. In fact their guts are highly effective killing machines, so once ingested the microbes are in fact destroyed. It’s a primitive form of ‘seek and destroy’.


Morris says, ‘The stomach-turning reaction to maggots is because most people know them from nasty encounters at their dustbins. But these are incidental maggots and are quite different from medicinal maggots.’

Diabetic patient Andrew Cochrane believes there is no yuk factor when it’s a choice of maggot therapy or leg amputation. In fact, he says, ‘it’s the medical practitioners who often balk at the idea’. Indeed, as US-based entomologist, physician, and biotherapy practitioner Ronald A Sherman notes: ‘Patients tend to have not only a morbid fascination with maggot therapy but also a willingness not often shared by the applying practitioner.’

Using maggots in wound therapy could very well be the subject of a TV medical drama – As the Skin Crawls, they could call it – but it’s efficient, safe and costs very little.

There may be a lot not to like about the thought of maggots wriggling in your wound, but it can literally save life and limb.


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