Maggot Therapy

Also called; Biodebridement, Maggot debridement therapy (MDT) or Larval therapy.

This is the controlled, therapeutic application of live blowfly (Lucilia sp) larvae ("maggots") into non-healing wounds to to aid in wound debridement (cleaning), disinfection and/or healing.It can also be termed "Therapeutic Myiasis" as we recall that maggot infestation on a living vertebrate host is called "myiasis".

Maggot Therapy (Picture Credit; Science Open)

"Despite our low cultural esteem for maggots, more and more clinicians and patients are turning to medicinal maggots for assistance with their wound healing. For most, the drawbacks of maggot therapy pale in comparison to the remarkable efficacy in treating even the most recalcitrant wounds"- Ronald A. Sherman,

Though It sounds medieval, Maggot therapy is an accepted part of modern medicine as Debridement is an essential component of wound care; the presence of devitalized tissue can impede the healing process.

History Of Maggot Therapy
The beneficial effects of therapeutic myiasis were first observed during the Napoleonic war by Larrey, who noted that soldiers whose wounds had become infested with maggots had an improved prognosis.
William Baer, while at Johns Hopkins University in Baltimore, Maryland, may have been the first person to have intentionally applied larvae to wounds in order to induce wound healing. During the late 1920's, he identified certain species, raised them in the laboratory, and used their larvae to treat several children with osteomyelitis and soft tissue infections. He presented his findings at a surgical conference in 1929. Two years later, after treating 98 children, his findings were published posthumously.
Throughout the 1930’s Maggot Therapy was performed routinely by Doctors until the discovery of new antibiotics and surgical techniques that came out during World War II. Maggot therapy was occasionally used during the 1970's and 1980's, but only when antibiotics, surgery, and modern wound care failed to control the advancing wound.

The emergence of antibiotic-resistant strains of bacteria such as methicillin resistant Staphylococcus aureus (MRSA) and the curiosity of researchers prompted the reemergence of larval therapy during 1970's & 1980's . As a treatment it meets the demands of clinical governance, being not only beneficial to the patient, but also being proven to be more cost-effective.

In January 2004, the U.S. Food and Drug Administration (FDA) granted permission to produce and market Medicinal maggots. Same year the British National Health Service (NHS) gave approval for maggot therapy. Presently, about 30 countries around the world are using Maggot therapy; In Africa, it is being used in Kenya & South Africa. In European Union, Canada, Japan, maggots are classified as medicinal drugs, needing a full market license.

Mechanism Of Action
Debridement; The maggots secrete a broad spectrum of digestive juice (collagenases, proteolytic enzymes, serine proteases) that selectively liquefy and absorb only necrotic tissue (extracorporeal digestion). Also Mechanical Debridement by the specific mandibles or “mouth hooks” of the maggots and their rough body which both scratch the necrotic tissue.

Disinfection; It was discovered that secretions from maggots (allantoin, urea, phenylacetic acid, phenylacetaldehyde, calcium carbonate, proteolytic enzymes, etc) have broad-spectrum antimicrobial activity, and microbes not killed by these secretions are subsequently ingested and lysed within the maggots. Maggot secretions have been found to dissolve biofilms.

Stimulation of healing; The alkalinity of maggot-treated wounds, along with the isolated allantoin and urea-containing compounds is responsible for wound healing. In fact, today, allantoin and urea are components of many cosmetics. Maggot secretions also;
 -stimulates the proliferation of fibroblasts and endothelial tissue ,
 -increases angiogenesis,
 -enhances fibroblast migration over model wound surfaces.
Using remittance spectroscopy to evaluate patients before and after maggot therapy, Wollina and colleagues found that vascular perfusion and tissue oxygenation surrounding the wound actually increased following maggot therapy. Zhang and colleagues are currently seeing evidence that maggot extracts may even stimulate the growth of neural tissue.

Uses/Indication

• Diabetic Foot Ulcer
• For debriding non-healing necrotic skin and soft tissue wounds including;

               -pressure ulcers,
               -venous stasis ulcers,
               -neuropathic foot ulcers,
               -non-healing traumatic or post-surgical wounds
               -infectious

• In diabetic and non-diabetic subjects for wound bed preparation prior to surgical closure.

Dosage & Administration
Maggots are applied to the wound at a dose of 5–10 larvae per square centimeter of wound surface area and are left within their dressing for 48–72 hrs. At that point they are satiated (as evidenced by increase in size), finished working, and can be removed and safely disposed.

Maggot therapy being a controlled therapeutic myiasis (maggot infestation on a live host) is controlled by;

selecting a safe and effective species and strain,

• chemical disinfection to make the maggots germ-free (sterile maggots),
• containing the maggots within special dressings(e.g maggot confinement dressings; Le Flap™,Biobag™ ) that prevent them from leaving the wound unescorted,
• quality control measures throughout the breeding and production processes.

Not all species are safe and effective. The maggots cleared for marketing in the United States belong to the (currently named) LB-01 strain of Phaenicia (Lucilia) sericata.

Advantages Of Maggot Therapy

1. Takes about 15-30 minutes to apply a secure dressing to keep the maggots in place
2. Low cost of treatment
3. Excellent safety record.
4. Simple enough that non-surgeons can use it to provide thorough debridement when surgery is not available or is not the optimal choice
5. Provide surgical quality debridement as an outpatient or in the home
6. Provides treatment for wounds infected by strains of methicillin resistant Staphylococcus aureus (MRSA)
7. As larvae are typically applied for 3 days, wounds are disturbed less frequently than conventional dressings that require changing everyday

Disadvantages

1. Bacteria like Pseudomonas aeruginosa, Escherichia coli, Enterococcus, Proteus are not attacked by maggots and in case of Pseudomonas even the maggots are in danger. Consequently, using maggots alone might lead to a change of bacteria cultures on the wound.
2. Ineffective in case of highly discharging or dried wounds
3. Medicinal maggots are highly perishable and susceptible to transportation problems and delays. Young, starving larvae require food, water, and oxygen, and they are temperature sensitive. Therefore they must be shipped by overnight courier, and their arrival should be timed no more than 24 h before their application to the wound. Delivery delays and exposure to extreme temperatures decrease their survival.
4. Occasionally the maggots may escape from the wounds and 1–2 weeks later become adult flies (“used maggots” and flies are essentially mobile fomites)
5. Local discomfort, itching, unaesthetic appearance to the patient along with cost of the therapy and short half life of maggots
6. It cannot be used in open wounds of body cavities as the environment is not suitable
7. Negative perception with which it is regarded by both patients and doctors; The 'yuk factor'

Side Effects
Minor bleeding,Pain,
Excessively induced exudates,
Increased body temperature,
Flu-like symptoms,
Allergic reaction,
Skin maceration
Discomfort.

Contraindications
Patients refusal.

Alternative Therapies

• Biotherapies like; apitherapy (application of honey) and application of leeches.
• Sonotherapy (with use of ultrasounds)
• Hydrosurgical therapy (with use of water jets)
• Hyperbaric Oxygen Therapy (HBOT)

Medical Maggots™ (Picture Credit; Live science)

Maggot Debridement Therapy (Picture Credit; btmcl)

NOTES
1) A. J. Horobin, K. M. Shakesheff, S. Woodrow, C. Robinson, and D. I. Pritchard, “Maggots and wound healing: an investigation of the effects of secretions from Lucilia sericata larvae upon interactions between human dermal fibroblasts and extracellular matrix components,” The British Journal of Dermatology, vol. 148, no. 5, pp. 422–933, 2003.

2) A. G. Smith, R. A. Powis, D. I. Pritchard, and S. T. Britland, “Greenbottle (Lucilia sericata) larval secretions delivered from a prototype hydrogel wound dressing accelerate the closure of model wounds,” Biotechnology Progress, vol. 22, no. 6, pp. 1690–1696, 2006.

3) Dariusz Waniczek, Andrzej Kozowicz, Małgorzata Muc-Wierzgoń, Teresa Kokot, Elżbieta Świętochowska, and Ewa Nowakowska-Zajdel, "Adjunct Methods of the Standard Diabetic Foot Ulceration Therapy,"  Evidence-Based Complementary and Alternative Medicine
Volume 2013 (2013), Article ID 243568 Chapter 3

4) P. E. Prete, “Growth effects of Phaenicia sericata larval extracts on fibroblasts: mechanism for wound healing by maggot therapy,” Life Sciences, vol. 60, no. 8, pp. 505–510, 1997.

5) R. A. Sherman, "Mechanisms of Maggot-Induced Wound Healing: What Do We Know, and Where Do We Go from Here?" Evidence-Based Complementary and Alternative Medicine
Volume 2014 (2014), Article ID 592419

6) R. A. Sherman, “Maggot therapy for foot and leg wounds,” International Journal of Lower Extremity Wounds, vol. 1, no. 2, pp. 135–142, 2002.

7) R. A. Sherman, "Maggot Therapy takes us back to the future of wound care: New and Improved Maggot Therapy for 21st Century" J Diabetes Sci Technol. 2009 Mar; 3(2): 336–344.

8) U. Wollina, K. Liebold, W. Schmidt, M. Hartmann, and D. Fassler, “Biosurgery supports granulation and debridement in chronic wounds—clinical data and remittance spectroscopy measurement,” International Journal of Dermatology, vol. 41, no. 10, pp. 635–639, 2002.

9) Wikipedia, "Maggot Therapy"

10) W. Robinson, “Stimulation of healing in non-healing wounds by allantoin occurring in maggot secretions and of wide biological distribution,” Journal of Bone and Joint Surgery, vol. 17, pp. 267–271, 1935

11) Z. Zhang, S. Wang, Y. Diao, J. Zhang, and D. Lv, “Fatty acid extracts from Lucilia sericata larvae promote murine cutaneous wound healing by angiogenic activity,” Lipids in Health and Disease, vol. 9, article 24, 2010.

12) Z. Zhang, S. Wang, X. Tian, Z. Zhao, J. Zhang, and D. Lv, “A new effective scaffold to facilitate peripheral nerve regeneration: chitosan tube coated with maggot homogenate product,” Medical Hypotheses, vol. 74, no. 1, pp. 12–14, 2010.