Maggot debridement therapy (also known asMDT,larval therapy, or simplymaggot therapy) is a type ofbiotherapy involving the introduction of live, disinfectedmaggots (fly larvae) into non-healing skin and soft-tissuewounds of a human or other animal for the purpose of cleaning out thenecrotic (dead) tissue within a wound (debridement), and disinfection.There is evidence that maggot therapy may help with wound healing.[1][2]
Maggot therapy improves healing inchronic ulcers.[1] Indiabetic foot ulcers there is tentative evidence of benefit.[3] ACochrane review of methods for the debridement ofvenous leg ulcers found maggot therapy to be broadly as effective as most other methods, but the study also noted that the quality of data was poor.[4]
The wound must be of a type that can benefit from the application of maggot therapy. A moist,exudating wound with sufficient oxygen supply is a prerequisite. Not all wound-types are suitable: wounds which are dry, or open wounds of body cavities do not provide a good environment for maggots to feed. In some cases it may be possible to make a dry wound suitable for larval therapy by moistening it withsaline soaks.[6]
Patients and doctors may find maggots distasteful, although studies have shown that this does not cause patients to refuse the offer of maggot therapy.[7] Maggots can be enclosed in opaque polymer bags to hide them from sight. Dressings must be designed to prevent any maggots from escaping, while allowing air to get to the maggots.[8] Dressings are also designed to minimize the uncomfortable tickling sensation that the maggots often cause.[9]
In maggot therapy, large numbers of small maggots consume necrotic tissue far more precisely than is possible in a normal surgical operation, and can debride a wound in a day or two. The area of a wound's surface is typically increased with the use of maggots due to the undebrided surface not revealing the actual underlying size of the wound. They derive nutrients through a process known as "extracorporeal digestion" by secreting a broad spectrum of proteolytic enzymes[13] thatliquefy necrotic tissue, and absorb the semi-liquid result within a few days. In an optimum wound environment maggots molt twice, increasing in length from about 2 mm to about 10 mm, and in girth, within a period of 48–72 hours by ingesting necrotic tissue, leaving a clean wound free of necrotic tissue when they are removed.[14]
Those flies whose larvae feed on dead animals will sometimes lay their eggs on the dead parts (necrotic or gangrenous tissue) of living animals. The infestation by maggots of live animals is calledmyiasis. Some maggots will feed only on dead tissue, some only on live tissue, and some on live or dead tissue. The flies used most often for the purpose of maggot therapy are blow flies of the familyCalliphoridae: the blow fly species used most commonly isLucilia sericata, the common green bottle fly. Another important species,Protophormia terraenovae, is also notable for its feeding secretions, which combat infection byStreptococcus pyogenes andS. pneumoniae.[18]
Written records have documented that maggots have been used sinceantiquity as a wound treatment.[19] There are reports of the use of maggots for wound healing byMaya, Native Americans, andAboriginals in Australia. Maggot treatment was reported inRenaissance times. Military physicians observed that soldiers whose wounds had become colonized with maggots experienced significantly less morbidity and mortality than soldiers whose wounds had not become colonized. These physicians includedNapoleon's surgeon-general, BaronDominique Larrey. Larrey reported during theFrench campaign in Egypt and Syria (1798–1801) that certain species of fly consumed only dead tissue and helped wounds to heal.[18]
I have frequently seen neglected wounds ... filled with maggots ... as far as my experience extends, these worms eat only dead tissues, and do not injure specifically the well parts.
The first documented therapeutic use of maggots in the United States is credited to a second Confederate medical officer Dr. J.F. Zacharias, who reported during the American Civil War that:
Maggots in a single day would clean a wound much better than any agents we had at our command ... I am sure I saved many lives by their use.
He recorded a high survival rate in patients he treated with maggots.[20]
DuringWorld War I,orthopedic surgeon William S. Baer recorded the case of a soldier left for several days on the battlefield who had sustainedcompound fractures of thefemur and large flesh wounds. The soldier arrived at the hospital with maggots infesting his wounds but had no fever or other signs of infection and survived his injuries, which would normally have been fatal. After the war, Baer began using maggot therapy atBoston Children's Hospital inMassachusetts.[21][22]: 169–71
In the USA: in January 2004, the FDA granted permission to produce and market maggots for use in humans or animals as a prescription-only medical device for the following indications: "For debriding non-healing necrotic skin and soft tissue wounds, including pressure ulcers, venous stasis ulcers, neuropathic foot ulcers, and non-healing traumatic or post-surgical wounds."[26][27]
The use of maggots to clean dead tissue from animal wounds is part offolk medicine in many parts of the world.[28] It is particularly helpful with chronicosteomyelitis, chroniculcers, and otherpus-producing infections that are frequently caused by chafing due to work equipment.[citation needed] Maggot therapy for horses in the United States was re-introduced after a study published in 2003 by veterinarian Dr. Scott Morrison. This therapy is used in horses for conditions such as osteomyelitis secondary tolaminitis, sub-solar abscesses leading to osteomyelitis, post-surgical treatment of street-nail procedure for puncture wounds infecting the navicular bursa, canker, non-healing ulcers on thefrog, and post-surgical site cleaning forkeratoma removal.[29]
However, there have not been many case studies done with maggot debridement therapy on animals, and as such it can be difficult to accurately assess how successful it is.[30]
^Tian, X; Liang, XM; Song, GM; et al. (September 2013). "Maggot debridement therapy for the treatment of diabetic foot ulcers: a meta-analysis".Journal of Wound Care.22 (9):462–9.doi:10.12968/jowc.2013.22.9.462.PMID24005780.
^Reames, Mark K.; Christensen, Chris; Luce, Edward A. (1988). "The Use of Maggots in Wound Debridement".Annals of Plastic Surgery.21 (4):388–91.doi:10.1097/00000637-198810000-00017.PMID3232928.
^Heuer, Heike; Heuer, Lutz (2011). "Blowfly Strike and Maggot Therapy: From Parasitology to Medical Treatment". In Mehlhorn, Heinz (ed.).Nature Helps. Parasitology Research Monographs. pp. 301–23.ISBN978-3-642-19381-1.
^abSherman, R. A.; Hall, M. J. R.; Thomas, S. (2000). "Medicinal Maggots: An Ancient Remedy for Some Contemporary Afflictions".Annual Review of Entomology.45:55–81.doi:10.1146/annurev.ento.45.1.55.PMID10761570.
^Sherman, Ronald A.; Morrison, Scott; Ng, David (2007). "Maggot debridement therapy for serious horse wounds – A survey of practitioners".The Veterinary Journal.174 (1):86–91.doi:10.1016/j.tvjl.2006.05.012.PMID16831562.
Van Der Plas, M. J. A.; Jukema, G. N.; Wai, S.-W.; Dogterom-Ballering, H. C. M.; Lagendijk, E. L.; Van Gulpen, C.; Van Dissel, J. T.; Bloemberg, G. V.; Nibbering, P. H. (2007). "Maggot excretions/secretions are differentially effective against biofilms of Staphylococcus aureus and Pseudomonas aeruginosa".Journal of Antimicrobial Chemotherapy.61 (1):117–22.doi:10.1093/jac/dkm407.PMID17965032.
Cazander, G.; Van Veen, K.E.B.; Bernards, A.T.; Jukema, G.N. (2009). "Do maggots have an influence on bacterial growth? A study on the susceptibility of strains of six different bacterial species to maggots of Lucilia sericata and their excretions/secretions".Journal of Tissue Viability.18 (3):80–7.doi:10.1016/j.jtv.2009.02.005.PMID19362001.
Cazander, Gwendolyn; Schreurs, Marco W. J.; Renwarin, Lennaert; Dorresteijn, Corry; Hamann, Dörte; Jukema, Gerrolt. N. (2012). "Maggot excretions affect the human complement system".Wound Repair and Regeneration.20 (6):879–86.doi:10.1111/j.1524-475X.2012.00850.x.PMID23110586.S2CID24568980.
Mumcuoglu, Kosta Y.; Ingber, Arieh; Gilead, Leon; Stessman, Jochanan; Friedmann, Reuven; Schulman, Haim; Bichucher, Hellen; Ioffe-Uspensky, I; Miller, J; Galun, R; Raz, I (1999). "Maggot therapy for the treatment of intractable wounds".International Journal of Dermatology.38 (8):623–7.doi:10.1046/j.1365-4362.1999.00770.x.PMID10487456.S2CID45118935.
Sherman, R. A.; Hall, M. J. R.; Thomas, S. (2000). "Medicinal Maggots: An Ancient Remedy for Some Contemporary Afflictions".Annual Review of Entomology.45:55–81.doi:10.1146/annurev.ento.45.1.55.PMID10761570.
