Cordylobia anthropophaga is a species of blowfly commonly known by several names, including the Tumbu fly, mango fly, or putzi fly. This insect causes cutaneous myiasis, a parasitic condition where its larvae develop within the skin of mammals, including humans and dogs. This type of myiasis is particularly prevalent in sub-Saharan Africa.
Lifecycle and Method of Infestation
The Tumbu fly’s lifecycle begins when an adult female lays 100 to 300 eggs. These are typically deposited in dry, sandy soil, often contaminated with feces or urine, or on damp clothing or bedding left outdoors to dry. They prefer shaded areas for oviposition.
Larvae, also known as maggots, hatch from the eggs within one to three days. These larvae can survive in the soil for 9 to 15 days without a host. Sensing the body heat of a nearby mammal, the larvae become active and burrow into the skin.
Inside the host, they develop through three stages, maturing in 8 to 12 days to the prepupal stage. The fully grown larva then exits the host, falls to the ground, buries itself, and pupates in the soil, emerging as an adult fly.
Signs and Symptoms of Myiasis
An infestation by Cordylobia anthropophaga results in a boil-like lesion on the skin, known as furuncular myiasis. Initially, a small red papule forms at the site of larval penetration, which gradually enlarges over several days. This swelling develops into a red, painful nodule, resembling a furuncle or boil.
A distinguishing feature of these lesions is a small central opening, or punctum, which the larva uses for breathing. This pore may discharge a clear or yellowish fluid. Individuals report itching, a sensation of movement beneath the skin, and increasing pain as the larva matures. While lesions can appear as a single boil, multiple infestations are common and are frequently mistaken for bacterial infections.
Treatment and Larva Removal
The primary goal of treating Cordylobia anthropophaga myiasis is the safe removal of the larva. One common and effective method involves occluding the larva’s breathing pore to induce it to emerge. Applying a thick, oxygen-blocking substance such as petroleum jelly, liquid paraffin, mineral oil, or bacon fat over the central opening suffocates the larva. This lack of oxygen prompts the larva to migrate outwards in search of air, bringing it closer to the skin’s surface.
Once the larva surfaces, it can be gently squeezed out by applying pressure around the lesion or carefully removed with forceps. It is important to avoid rupturing the larva during removal to prevent an inflammatory reaction. A medical professional may perform a small surgical incision to enlarge the punctum, facilitating the complete extraction of the larva. After removal, the wound should be thoroughly cleaned to prevent secondary bacterial infections, and topical antibiotics may be applied.
Prevention and Geographic Risk
Preventing Tumbu fly infestation involves disrupting the fly’s method of egg deposition and larval penetration. Ironing all clothing, bedding, and towels thoroughly on both sides, especially seams, is an effective measure. The heat from the iron destroys any eggs or newly hatched larvae present on the fabric.
If ironing is not feasible, drying laundry in a machine dryer on a hot cycle is an effective way to kill eggs and larvae. Avoid drying clothes directly on the ground, on low bushes, or in shady outdoor areas in regions where the Tumbu fly is prevalent. The Tumbu fly is found throughout sub-Saharan Africa, making travelers and residents in this region susceptible to infestation.