Also known as the mango fly, the tumbu fly, or the skin maggot fly, the putzi fly (Cordylobia anthropophaga) is an African blow-fly species. Like many other blow-fly species, putzi fly larvae are parasitic. This means that they burrow beneath the skin of a host animal, where they feed on subcutaneous tissue until they are ready to emerge several days later. Often, these hosts are human, causing a condition known as cutaneous myiasis. In this article, we explore the symptoms of putzi fly infection, as well as the easiest ways to avoid it.
Life Cycle and Distribution
The putzi fly's scientific name, anthropophagi, translates roughly from the Greek for "human eater"; an accurate moniker considering its flesh-eating tendencies. Typically, female putzi flies lay their eggs in sand or soil contaminated with human or animal feces. The larvae hatch after a brief incubation period of up to three days, after which they can survive for around two weeks before finding a suitable host. Once a host (usually a large mammal) has been found, the larvae penetrate the skin, then spend eight to 12 days feeding before emerging as fully developed maggots ready to pupate into adult flies.
Putzi flies are found in tropical regions across sub-Saharan Africa. Their range has expanded in recent years as a direct result of climate change, which has caused higher temperatures and increased seasonal rainfall in many parts of the continent.
How Putzi Flies Affect Humans
In areas of human habitation, people serve as the ideal host for putzi fly larvae. The most usual method of infection occurs when the putzi fly female lays her eggs in clothing left out to dry. The larvae then hatch in the seams, before burrowing beneath the skin of the unfortunate wearer. Symptoms typically take up to two days to manifest themselves and can range from vague discomfort and itchiness to insomnia and severe pain. Within six days, the host develops multiple boil-like sores or furuncles. Eventually, these will burst, secreting pus, blood, and ultimately, the maggot itself.
How to Avoid Infection
If you're planning a luxury Tanzanian safari or a trip to a five-star beach resort in Kenya, your clothes are likely to be washed using modern laundry facilities. This significantly reduces the likelihood of exposure to putzi fly larvae. However, if you're opting for a self-drive safari or long-term stays in backpacker accommodation, you will probably end up hand-washing your clothes at least once. In this case, the first and most effective way to avoid infection is to iron your clothes, as the heat kills the eggs before they can hatch. If you don't have access to an iron, hang your clothes up inside and never leave them to dry on the ground.
How to Diagnose Infection
In the tropics, sores and minor infections are common; so how do you distinguish a putzi fly parasite from a mosquito or flea bite? At first, it's almost impossible, as the infection initially manifests itself as a small red pimple, most often located on the back of the host's arms, or on their waist, lower back, or buttocks. Over the course of a few days, however, the pimple expands, eventually developing a white head. One key method of identification is a pinprick opening in the center of the boil, through which the putzi larva breathes and expels bodily fluids. In the final stages of infection, it is sometimes possible to see the tail of the maggot moving beneath the skin's surface.
How to Treat Sores
Although putzi fly larvae will eventually leave your body of their own accord, it's best to remove them as soon as possible. Once identified, the easiest way to treat a putzi fly sore is to cover the opening of the boil with Vaseline, effectively cutting off the larva's air supply. The maggot will then come to the surface and can be gently squeezed out using your thumbs (in much the same way that one might squeeze a blackhead or a pimple). It is important to thoroughly disinfect and dress the resulting wound. Do not incise the sore, or use forceps or tweezers to extract the larva as this may cause inflammation and secondary infection (especially if the maggot ruptures). If this happens, prescription antibiotics may be necessary.
Often a patient will have multiple putzi fly infections. Since the larvae do not always hatch at the same time, be on the look out for further sores.