When Human Botflies Attack!

Thought that this might appeal to (no one!) some members of the audience (no one!) that have a strong disposition (no really, I mean it-- no one!). Vanessa Serrao, a nature film maker based out of Silver Spring, MD, discovered that which horror movies are made of: a human botfly larva feeding on her scalp. Having recently returned from Beliz, she discovered an oozing sore on the back of her head-- and to her displeasure, discovered that it was, in fact, a parasite. This brave lady and her equally brave husband, Greg Hiemenz, filmed themselves removing the larva from her head. An entomology professor of mine once said that the only "true" entomologists were the ones that would allow themselves to be infected with botfly larvae in order to study the effects of the parasitism from a very intimate perspective. Let's hope he was kidding...

Human botfly larvae (Dermatobia hominis) are deposited inside humans via mosquitoes and in some cases, muscoid flies. Here's how it works: an adult female botfly captures a mosquito and attaches her eggs to its body before releasing it. When the infected mosquito feeds on a human, the botfly larvae drops onto the human and enters the skin through the bite made by the mosquito. The botfly larvae then reside and feed within the subcutaneous layers of the host's flesh for approximately 8 weeks. After the 8 weeks of feeding, the larvae drops out of its host in order to pupate. The resulting insect is a large, hairy fly that closely resembles a dull grey blowfly (1).



The relationship between the botfly larvae and the mosquito is an example of phoresy, which is an "association between two organisms in which one (e.g., a mite) travels on the body of another, without being a parasite" (2). Whereas, the relationship between the botfly larvae and the human is obviously parasitic in nature. There are other species of botflies that infect other types of mammals-- livestock, apes, dogs, etc. in much the same manner.

Human botflies are not especially dangerous to humans; unless the wound gets infected, you are pretty much good to go once the larvae drops out of the flesh. However, if the larvae is ripped from the wound and not removed completely, an infection could occur. Either way, I recommend that you see a doctor so that he may prescribe a topical antibiotic ointment.


(1) Featured Creatures. University of Florida Institute of Food and Agricultural Sciences. 22 September 2009. http://entomology.ifas.ufl.edu/creatures/misc/flies/human_bot_fly.htm

(2) "Phoresy." Oxford American Dictionary.