The mangoworm is the larval stage of the Tumbu fly, scientifically known as Cordylobia anthropophaga. This parasitic condition, called furuncular myiasis, occurs when the larva penetrates the skin of a mammal, including humans and pets. The fly is endemic to sub-Saharan Africa, where it is a frequent cause of skin infestation. While the condition is generally temporary and localized, it causes significant discomfort as the larva develops beneath the skin surface.
Identification and Life Cycle of the Tumbu Fly
The Tumbu fly, also known as the mango fly or putzi fly, is a species of blow-fly belonging to the family Calliphoridae. The adult fly is non-parasitic, but the female lays 100 to 300 eggs. These eggs are usually deposited in dry, sandy soil contaminated with animal feces or urine, or sometimes on damp clothing.
The eggs hatch quickly, often within one to three days, producing the first-stage larvae, which are the mangoworms. These larvae must find a warm-blooded host to continue their development, and they can remain viable in the soil for up to 9 to 15 days while waiting. Once a host is located, the larva burrows into the skin and grows rapidly through three stages, or instars, over approximately 8 to 12 days.
During this period, the larva reaches its full size, up to 15 millimeters long, and develops tiny spines that help anchor it within the host’s subcutaneous tissue. After completing its feeding and growth phase, the mature larva exits the skin, drops to the ground, and buries itself. It then enters the pupal stage in the soil, completing its metamorphosis into the adult Tumbu fly.
Transmission: How Infestation Occurs
Infestation begins when the host comes into direct contact with the newly hatched larvae in the contaminated environment. The larvae are capable of penetrating unbroken skin, and the process of burrowing beneath the surface can occur in less than 25 seconds upon contact.
A common vector for human infestation is clothing or bedding that has been laid on the ground or hung outside to dry. When a person wears contaminated clothing, the warmth and moisture of the skin stimulate the eggs to hatch, and the larvae immediately penetrate the skin.
Infestation can also occur through direct contact with contaminated soil, sand, or bedding, particularly when walking barefoot or resting on the ground in endemic areas. Dogs and rodents are the primary natural hosts, but humans become accidental hosts. The larvae typically target areas of the body that have been in contact with the contaminated material, such as the buttocks, back, or areas covered by the laundry.
Recognizing Symptoms and Safe Removal
The presence of a mangoworm larva causes a skin lesion that mimics a painful boil. Initial symptoms often include a small, itchy red bump that may be mistaken for a mosquito bite or an insect sting. As the larva grows beneath the skin, the lesion rapidly enlarges, becoming firm, painful, and tender to the touch.
A distinguishing feature of this infestation is the small, dark opening at the center of the lesion, which serves as the larva’s breathing hole. Patients may report an unusual creeping sensation or intermittent sharp pain caused by the larva’s movement or feeding. If the lesion becomes secondarily infected with bacteria, pus may form, and the surrounding skin will appear inflamed and swollen.
Safe Removal Techniques
Safe, non-surgical removal is the preferred initial approach, aiming to suffocate the larva and force it to emerge. This method involves applying a thick layer of occlusive substance, such as petroleum jelly, liquid paraffin, or heavy oil, directly over the breathing hole. The occlusion cuts off the larva’s air supply, causing it to partially emerge in an attempt to breathe.
Once the larva begins to emerge, typically after several hours, it can often be gently expressed with light finger pressure around the lesion, similar to removing a splinter. Avoid using sharp instruments, such as forceps or needles, to extract the larva, as tearing it can leave fragments behind. Fragments trigger a severe inflammatory reaction and increase the risk of a deep bacterial infection, often necessitating medical intervention. Medical attention should be sought immediately if the larva cannot be easily removed, if signs of a worsening infection develop, or if multiple lesions are present.
Practical Prevention Strategies
Preventing mangoworm infestation relies heavily on meticulous hygiene practices in regions where the Tumbu fly is present. A primary strategy focuses on the proper handling of laundry, as damp clothing is a common point of contact for the eggs. Clothes should never be dried on the ground, and if drying outdoors is necessary, they should be removed promptly.
All clothes, particularly underwear and linens, should be thoroughly ironed after being dried outside. The heat from the iron kills any eggs or larvae deposited in the fabric. Using a tumble dryer or drying laundry indoors entirely eliminates the risk of fly contact.
Limiting direct skin contact with potentially contaminated soil is also important. Pets, which are common hosts, should be inspected regularly for suspicious bumps, and their bedding should be washed frequently in hot water and dried completely. Maintaining a clean yard environment by removing feces promptly and discouraging pets from lying in damp, shady areas further reduces the breeding grounds.