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Maggots

Scientific Name(S): Phaenicia sericata; Lucilia caesar, Pharmia regina

Common Name(S): Maggot, fly larva, grub, botfly maggot, "viable antiseptic," "living antiseptic," "surgical maggot"

Biology: Maggots are the larvae of various flies. The species Phaenicia sericata (green blow fly) has been used successfully in maggot therapy for many decades. The life cycle of those used in medicine begins with the laying of eggs by the adult female on meat or other substrate suitable for the larvae to feed on. The eggs hatch within one day, and the larvae then proceed to feed and grow. After 5 to 7 days, they become sessile, non-feeding pupae. After about 2 weeks of pupation, the adults emerge and the females begin laying eggs about five days later.

Larvae-rearing in the clinical setting can be a simple, low-cost procedure if done correctly. A report on species Lucilia sericata (Meigen) evaluates a sterile mixture of pureed liver and agar as growth medium. This method was not only inexpensive but provided longer storage capacity and no progressive decomposition or odor problems.

Uses of Maggots

Maggots have been used to promote wound healing and also to treat abscesses, burns, cellulitis, gangrene and ulcers. The most common use of maggots in surgery has been to prevent bone destruction, deformities and other effects of recalcitrant osteomyelitis.

Side Effects of Maggots

Surgical maggots do not appear harmful to living tissues but produce intense pruritus. Maggots can transmit parasitic disease, and larval ocular invasion has occurred.

Toxicology: Surgical maggots in themselves do not appear harmful to living tissues although it should be noted that maggots of screwworms can cause serious tissue damage. The surgical organisms, however, produce intense pruritus. Most patients adapt to this, but some require mild sedation.

Non-surgical maggots are commonly used as fishing lures. At least one report has described delayed-onset asthma in an angler who used Calliphora (blue bottle) larvae for bait. The patient was found to have circulating IgG antibody to a larval extract, and symptoms suggestive of immune complex disease subsequently developed. It has been suggested that dyes used to enhance the effectiveness of maggots as fishing lures can induce bladder cancer. A case-control study of more than 1800 subjects found no evidence of an association between the dyes and bladder cancer; however, the number of subjects who used dyed maggots in fishing was small so that an actual association may have escaped detection.

Maggots can transmit parasitic diseases resulting in severe destruction of tissues of the ears, nose and throat. This problem is common in India, where it occurs most frequently from September to November. This larval invasion has also been reported in the eye. One case report details the invasion of the ocular orbit of a man by maggots. This infestation was treated successfully by classical wound-cleaning therapy. Another case reports cuterebra larva in the conjunctiva of a boy suffering from decreased vision and subretinal hemorrhages. Successful removal was performed after positive identification of this offending agent by light microscopy. A third case of ophthalmic invasion by larva is reported, this time with successful removal by photocoagulation with an argon green laser resulting in good visual recovery.

Summary: Maggots have long been known to promote the healing of wounds without generally causing harm to living tissues. The use of surgical maggots experienced a certain popularity among surgeons during the 1930s and 1940s, but this waned with the development of antibiotic drugs. Nevertheless, maggots have been used successfully in recent years when other methods of treatment failed. Examples of maggot therapy include its use in bone destruction/infection and poorly healing wound debridement, including bedsores and other ulcers. Their medical use requires close supervision to ensure that secondary infections or other invasive complications do not arise. Other uses of maggots include "forensic entomology." Surgical maggots may not be harmful to living tissues but may cause itching. Unwanted larval invasion has occurred in the eyes, ears, nose and throat.