Production of Sterile Maggots
Myiasis
4 Clinical Application of Maggots
The Classical Free-Range Maggot Dressing System
The Containment-Bag Maggot Dressing System (Biobag)
Indications for Maggot Debridement Therapy
Adverse Effects and Risks of Maggot Therapy
Perspectives
Cost Effectiveness
Frequently Asked Questions
Sterile Maggot Suppliers
1 Introduction
Nature's Vast Pharmacy
Many people have their doubts about using maggots as medicine. However, they should bear in mind that a vast number of drugs come from nature's pharmacy.
Hirudin, a pharmaceutical agent used to dissolve blood clots, is a good example. This naturally occurring anticoagulant was isolated from the saliva of the medicinal leech. Hirudin serves to keep the blood flowing freely so that the leech can easily ingest it after biting its host. The salivary secretions of bats and snakes contain similar anticoagulants. To this day, the well-known antibiotic penicillin is fermented from a mold that produces the compound to kill its bacterial competitors. The Cantharanthus roseus plant is a natural source of antineoplastic alkaloids (vinblastine and vincristine) used to destroy malignant tumors. The drugs derived from this plant alone net more than $ 180 million in sales each year. The list goes on and on.
Few people realize just how much the pharmaceutical industry depends on natural organisms for drug manufacture. Of all prescription drugs sold, 25 % are derived from plants, 13 % from micro-organisms, and 3 % from animals. Accordingly, over 40 % of our pharmaceutical drugs come from nature.
Insects are a real treasure-trove of raw materials for drug manufacture. They produce a variety of active biochemicals, including sex pheromones, alarm pheromones, defensive substances, and venoms. For example, honey bee venom has long been used to treat arthritis, and butterfly, beetle, and wasp venom extracts appear to be effective in fighting cancer.
How and why did these useful substances come to exist? The secret lies in organic evolution. In the course of its phylogenic history, each living organism has evolved into a living chemical factory that produces the substances it specifically requires to survive in a hostile environment.
Millions of years of natural selection and adaptation have turned the most diverse organisms into chemists of immeasurable ingenuity—true masters in solving some of the same biological problems that also undermine the health of humans and other organisms.
The world wars waged in the first half of the 20th century brought devastation and great suffering to humankind. War injuries often resulted in incurable infections of the bone. In many cases, limb amputation was the only recourse for their survival. This dark picture was slightly brightened by countless reports of soldiers whose maggot-laden wounds were free of infection. Soon it became clear that the maggots were responsible for saving many lives and limbs. Thus maggot debridement therapy (MDT) was born.
Indeed, Hippocrates' maxim is as applicable today as it was some 2 400 years ago: “medicus curat, natura sanat” (the doctor administers the cure, nature does the healing).
2 Maggots
On Flies and Maggots
The Greek philosopher Aristotle (384-322 BC) named the fly “Diptera”. The Greek word “dipteron” means “two-winged”, referring to the single pair of functional wings that distinguish the fly from virtually all other insects. When working on his system of taxonomic classification of living organisms, or Systema naturae, published in the 18th century, Carl von Linné (Linnaeus, 1707-1778) adopted Diptera as the taxonomic name for the order of insects to which all true flies belong.
The origin of the dipterans is unknown. The oldest known fossils date back to the Triassic period and are some 210 to 220 million years old. These relicts mainly consist of the wings of adult flies. Signs of other stages of early fly development are practically non-existent.
The coexistence of flies with humans and domestic animals (synanthropy) has left notable marks in the history of humankind. Flies gained a reputation as pests, parasites, and carriers of harmful diseases. Written records and cult objects surviving from various periods testify to the explosive multiplication of fly populations during wars, famines, and other catastrophes. In all of these periods, people's attention was most strongly drawn to the seemingly apocalyptic plagues of flies that occurred throughout history.
The historical narratives cited below underline the timelessness and the global impact of the fly problem. The best known reference to plagues of flies is probably that in the Old Testament book of Exodus:
“This is what the Lord says: Let my people go so that they may worship me. If you do not let my people go, I will send swarms of flies on you and your officials, on your people and into the houses. The houses of the Egyptians will be full of flies, even the ground where they are. And the Lord did this. Dense swarms of flies poured into Pharaoh's palace and into the houses of his officials, and throughout Egypt the land was ruined by the flies.” Exodus 8:20-21 and 8:24, NIV Version, 1984
Fly populations multiply rapidly in warm weather and on corpses. The military physician Ambroise Pare (1510-1590), who reported on the Battle of Saint Quentin (1557), described this phenomenon as follows:
“We saw more than half a league round us the earth all covered with the dead; and hardly stopped there, because of the stench of the dead men and their horses; and so many blue and green flies rose from them, bred of the moisture of the bodies and the heat of the sun, that when they were up in the air they hid the sun. It was wonderful to hear them buzzing; and where they settled, there they infected the air, and brought the plague with them.”
(Quoted from: Ambroise Pare, Journeys in Diverse Places. The Harvard Classics. 1909-14)
Development Cycle of the Fly
There are over 100 000 species of flies, representing a variety of shapes and sizes (morphology), of habitats, and of behaviors. Yet they all have in common a 4-stage “complete” (holometabolous) metamorphosis, by which they develop through the stages of egg, larva, pupa, and finally adult (Fig. 1). As an example, the blowfly life cycle will be described in more detail. Female flies lay masses of up to 200 eggs, usually on dead bodies and decaying meat, but also on open wounds. Flies have special sensory organs that enable them to immediately recognize decayed flesh that is suitable for feeding and egg laying. The adult female unfurls its ovipositor (Fig. 2) and lays (“blows”) hundreds of its eggs on the meat. Hence the name blowfly.
Fig. 1 Immature fly stages. A: Eggs of Phoenicia (= Lucilia) sericata. B: Hatching first instar larvae
A female fly can lay up to 3 000 eggs in her lifetime. The number of eggs laid is determined by the size of the female and by the quality and quantity of food she consumes. On a protein-rich diet, a female fly may start to lay