Jwc ewma final indd

J O U R N A L  O F WO U N D  C A R E   Vo l   2 2 .  N o   1 .  E W M A   D o c u M E N t   2 0 1 3

Larvaedebridement

therapy

T

he removal of devitalised tissue is an 

essential component of wound care. 

Larval therapy, also known as maggot 

debridement therapy (MDT) or biosurgery, is a 

form of mechanical debridement whereby live 

maggots, raised in sterile conditions, usually Lucilia 

sericata (common green bottle fly), are placed 

on necrotic/sloughy wounds. Maggot secretions 

contain antibacterial substances that reduce 

bacterial load by exerting a bacteriostatic effect, 

and proteolytic enzymes cause eschar degradation 

by disrupting the tissue collagen matrix. These 

actions promote wound healing and amplify 

human fibroblast and chondrocyte growth.

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Larval therapy has been around for the last 400 years 

and has been primarily used for debridement of 

wounds when traditional methods of debridement 

(autolytic, mechanical or surgical) are unsuccessful.

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During the First World War, Baer successfully used 

sterile larval therapy in the treatment of leg ulcers 

and osteomyelitis.

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 With the development of 

antibiotics and advanced surgical technique, the use 

of larval therapy decreased and it was only used in 

chronic wounds as a last resort.

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 However, in recent 

years, the treatment is re-emerging, due to the rise 

in chronic wounds and the emergence of antibiotic-

resistant strains of bacteria, such as MRSA.

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Action

The actions of the larvae are threefold:

• 

Debridement

• 

Antimicrobial

• 

Stimulation of healing.

The larvae feed on necrotic tissue and exudate 

within the wound, thereby debriding it of 

devitalised tissue. The digestive juices secreted 

by larvae contain proteolytic enzymes, 

including trypsin-like and collagenase, and 

these selectively debride necrotic tissue, leaving 

viable tissue unharmed.

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 The movement of 

the larvae stimulates exudate production, thus 

increasing irrigation of the wound and assisting 

in the removal of bacteria;

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 the larvae ingest 

the liquefied tissue, neutralising the bacteria in 

their gut.

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 Additionally, bacteria that are not 

destroyed in the acidic alimentary canal are 

contained within a tubular structure, known 

as the peritrophic membrane, thus preventing 

contamination.

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 Larvae also inhibit bacterial 

activity by producing inhibiting secretions. 

Steenvoorde and Jukema

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 argue that adequate 

numbers of larvae are necessary to eradicate some 

Gram-negative species such as Escherichia coli; 

however, Van de Plas

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 contends that the larvae are 

antibacterial and useful in the eradication of biofilms. 

The larvae secretions contain alkaline components, 

thereby altering the PH of the wound and enabling 

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