Blowfly Strike and Maggot Therapy: From Parasitology to Medical Treatment

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Patients, especially elderly and diabetic ones, may develop chronic wounds on the leg and foot, so called ulcers, which are open sores that go through the skin. These often tend not to heal due to insufficient circulation, will eventually get infected, and might result in serious consequences such as amputation. Physicians all over the world are involved in the daily conflict as to how to treat such wounds, which are even when not life threatening very unpleasant for these patients as they usually have a strong smell and produce continuous pain. Within the last 20 years the treatment of wounds has not been based on a dry dressing but on a wet dressing (products such as hydrogel) and healing as the primary goal is obtained in some cases. Chronic wounds will heal only when the insufficient circulation is stopped. Most often it is required that all the dead material is removed from a wound, therefore a debridement of the wound is undertaken. Although there is no clear evidence that debridement is useful for wound healing at all, several techniques are in use. One of these is forced myiasis, MDT. Maggot debridement therapy (MDT) is a very efficient debridement technique and otherwise necessary amputations are avoided in some cases. For this therapy Lucilia spec. are the least invasive fly larvae tested for MDT and Lucilia sericata is in use in most places of the world. Other, more frequently found species of Lucilia are in use in some countries as well.

As maggots are fly larvae and they live on the patients wound they usually do not distinguish between dead and vital tissue and must be used in correct doses. Therapy should be stopped when pain occurs or bleeding is observed. The fly larvae combat some multiresistant bacteria, for example MRSA, but many gram-negative bacteria are contra-indicated as they might kill the fly larvae. The spit of the fly larvae contains a powerful mixture of enzymes and protein-based antibiotics, both of which are under evaluation for their use as a pharmaceutical drug. Either these compounds isolated from maggots or well-dosed fly larvae can be used for debridement of chronic wounds. Acute dehiscent wounds can be debrided efficiently by maggots and closed afterwards by other standard techniques for fast healing.

Larval treatment costs are in the same range or slightly higher compared to standard treatment when used for leg ulcers. Compared to products such as hydrogel no additional benefit was found in all available randomized clinical studies on fly larvae treatment on chronic wounds. Therefore, MDT should be used for selected patients only, especially as there is no full market authorization in Europe or anywhere else in the world apart from USA.