Meet the Human Botfly, Dermatobia hominis. Adult human botflies are stout-bodied flies. They have no active mouth parts and thus do not feed. They are found in Central and South America, and mostly specialize on cattle. However, it is not uncommon for humans to get in contact with them.
So far, so good. Flies without mouth parts cannot be much of an annoyance, right? Yes they can. When it comes to reproduction, the female botfly catches a female mosquito and lays its eggs on the mosquito. Pests disturbing each other are still fine with me.
Now comes the evil part, once the mosquito bites a host, the fly larva hatches and digs through the skin of the victim. Once inside the flesh it forms a kind of tumor, called a warble (even the name sounds scary), where it rests and eats. It breathes through a tiny opening in the skin. In the beginning it is usually not noticed, but it grows up to a size 20mm and has rows of hooks on its body, to keep it in place. This definitely will cause a swollen, itchy and painful lesion.
Now, even though this might be disgusting, the good news is that there are no dangerous diseases transmitted if it should happen to you on your travels. There are various easy ways of removing the maggot, e.g. using your fingers and pressure to pop it out, or sealing the breathing hole and forcing the larvae to come out.
I never really liked flies, except maybe as pet lizard food, but this really is scary, and if it should ever happen to anybody, it will for sure top any other holiday pest story. The peak fly season is about to start here, and I am happy I am on a different continent, where we only have to control “harmless” houseflies, that will be attracted by our Luminos traps rather than our flesh.
On a side note: There are more botfly species, which are mostly specialized on animals and not necessarily use mosquitoes as a vector. For example, there is a species that catches houseflies, holds them in a tight grip and then lays its eggs near to the wings of the caught housefly. Once the housefly sits on an animal, the eggs hatch and the whole warble thing (as described above) takes place.