Maggots, the larval stage of flies, can indeed interact with humans, sometimes consuming human tissue. Their feeding habits range from natural decomposition to specific medical applications. Understanding these interactions requires distinguishing their typical diet from human infestation.
Maggots and Their Natural Diet
In their natural environment, maggots primarily function as decomposers, playing a crucial role in nutrient recycling. These soft-bodied larvae are scavengers that consume decaying organic matter. Their diet includes a variety of materials rich in proteins and nutrients, such as carrion (dead animals), rotting vegetation, and spoiled food.
Flies lay their eggs on these decomposing materials. Maggots possess specialized mouthparts and oversized salivary glands that enable them to digest decaying material efficiently. They secrete enzymes that break down complex molecules into simpler compounds, which they then ingest. This process helps break down organic waste, returning nutrients to the soil for plant growth.
When Maggots Interact with Humans: Myiasis
When maggots infest the living tissue of humans or other animals, the condition is known as myiasis, also called flystrike. This parasitic infestation occurs when certain fly species lay eggs on or near a living host, and larvae develop inside, feeding on its tissues. Myiasis often occurs in tropical and subtropical regions, and individuals with open wounds or poor hygiene are at a higher risk.
Flies transfer larvae by depositing eggs directly into open wounds, sores, or near body orifices. Some lay eggs on intact skin, or attach them to other insects like mosquitoes, which then transfer larvae during a bite. Once hatched, larvae burrow into the skin or wound. While many species are attracted to and feed on necrotic (dead) or decaying tissue, some can invade and consume living tissue.
For instance, the New World screwworm is known to feed on living tissue and can cause significant damage, sometimes even leading to severe complications. Other species, such as the human botfly or the tumbu fly, lay eggs that hatch and painlessly burrow into unbroken skin, creating boil-like lesions. These larvae develop within the host’s living body. The severity of myiasis depends largely on the fly species involved and the location of the infestation.
Beneficial Applications in Medicine
Certain species of maggots have been intentionally used in medicine for centuries, a practice known as maggot debridement therapy (MDT) or larval therapy. This therapy involves introducing live, sterilized maggots to non-healing wounds to clean them and promote healing. The most commonly used species for MDT is the green bottle fly.
These medical-grade maggots selectively consume necrotic, sloughy, and infected tissue without harming healthy living tissue. They achieve this by feeding on dead tissue and secreting enzymes that liquefy necrotic material for ingestion. In addition to debridement, maggot secretions contain antimicrobial compounds that help reduce bacterial loads, including antibiotic-resistant strains like MRSA. This process also promotes wound healing by stimulating tissue growth and improving blood circulation. MDT is considered an effective method for cleaning chronic wounds, often more rapidly than conventional dressings, and is beneficial for ulcers and other complex wounds.