In early May, the National Institute for Communicable Diseases (NICD) sparked panic when they confirmed an outbreak of bot fly larvae infestations in the North West Province, with increasing sporadic cases occurring in Gauteng.
The bot fly larvae in question are those of the Tumbu Fly (also known as the ‘mango’ or ‘putsi’ fly), renowned for using dogs, rodents and even humans as a host during the larvae stage and causing a horrifying condition known as cutaneous myiasis – an infestation of the skin by developing larvae.
How do people get infected?
The Mango fly deposits eggs usually on urine or faeces-contaminated sand, soil or clothing. Once they hatch, the larvae burrows into the skin of a warm-blooded host, typically dogs or rodents, but humans also become accidental hosts
The larvae then grow and fatten up in the subcutaneous tissue and after 8-12 days, a boil forms and develops a small opening through which the larvae can breathe. The larvae then fall to the ground where they bury themselves in order to go into its final stage of growth before turning into an adult fly.
According to the NICD, “The increase in the number of cases is most likely related to the recent marked increase in seasonal rainfall, leading to the expansion of the fly’s normal range, namely the warmer northern and eastern parts of the country,”
Once the skin has become infected with the larvae, it is critical to get treatment straight away to prevent bacterial infection. Petroleum jelly (Vaseline) or liquid paraffin can be applied to the boils or lesions to suffocate the larvae and lubricate the cavity in the skin. Following the treatment, the larvae should then emerge from the skin or can be squeezed out using finger pressure followed by a course of antibiotics. Infected individuals are advised against using forceps or other instruments to extricate the maggots as inflammation or secondary infection is more likely if the maggot and/or skin is damaged.
How to prevent becoming infected
When you hang your newly laundered clothes outside, a female fly can mistake the warm damp clothes for animal faeces, so she will lay her eggs on the clothes. To prevent the eggs from being transferred from clothing to your skin, it’s important to take the following precautions:
- Iron all your clothes, especially underwear, baby clothes, and linens
- Alternatively, do not wear your clothes for 48 hours after they have dried
- Do not leave your washing to dry on the ground
- Use a tumble drier in the rainy season to kill all the eggs
- Make sure your clothes line is in direct sunlight at all times to facilitate fast drying
- Keep the grass very short under the clothes line
- Fence in the clothes line so that the area around cannot be contaminated by dogs
- Affected dogs should be dipped in an appropriate insecticide solution for prevention of tick or flea infestation, under veterinary guidance
- Ask the Pest Control Specialists to treat your yard with a residual spray treatment that will lower the possibility of Mango flies breeding in the area.