Human Bot Fly – Piotr Naskrecki (2015)

Piotr Naskrecki achieved what many tropical biologists (including the author of this post) tried but failed multiple times: raising a tropical Human bot fly (Dermatobia hominis). This parasite is frequently covered by major TV channels since it is quite gruesome to the unititiated and most certainly attracts viewers. In my opinion this is the best bot fly documentary ever. In the video Dr. Naskrecki outlines the life cycle very well with the calmness of an entomologist without drama. You can find the details of his experience in his entomology blog.

I don’t want you to think that it is “creepy” or “weird”. It is simply a documentation of an interesting organism, who happens to develop in the skin of large mammals. — Piotr Naskrecki

This Neotropical fly has a fascinating natural history with a parasitic larvae stage. If you spend some time in the new world tropics you will eventually meet this rather common parasite. It is so common that you can observe it in many other non-human mammals such as monkeys or even in domesticated animals such as cats or cows. Although it uses mosquitoes as vector to find a host they also lay their tiny eggs into places where unsuspecting victims may brush while passing. In Humans bot fly eggs can hatch and bury themselves in rather inconvenient places such as the scalp and even inside the eyelid. People wearing contact lenses must avoid touching their eyes with muddy fingers which may carry the notorious eggs. Best way to avoid bot flies is to wash and dry the cloths. Unwashed field cloths can increase bot fly infection if worn next day.

Bot flies secrete antibacterial chemicals to keep the host healthy and keep its breathing hole (warble) on the skin open. During removal special attention must be paid to prevent the maggot from dying while inside the skin since this may lead to very serious infection. Infection of the scalp or the eyelid may result in unwanted complications.

In the old world there’s another similarly parasitic fly known as the warble fly that also infects mammals including Humans. One bot fly species (Cuterebra emasculator) infects squirrels and chipmunks in Eastern North America. Parasitic way of life have evolved multiple times among Dipterans and some flies have highly specialized hosts. Phorid flies for example are well known for their attacks on social insects and are shown to be contributing to the colony collapse disorder in honeybees.