How do you get a bot fly in your head? (Or, Just how freaked out about this should I be??)
This is a true story, and bot flies that attack other mammals are common around the world. Bot flies that will infest humans, however, are rare. Notice that nearly all bot fly stories have one thing in common–a visit to forested areas of Central or South America. If you aren’t there, or visiting there, don’t worry!
The “human” bot fly is really a primate bot fly–it normally infests monkeys. The primate bot fly belongs to the Genus Dermatobia, in the fly Family Oestridae. This family of flies are also known as warble flies, and infest all manner of mammals, including horses, cats, and mice. (One group, called “snot bots”, specializes in living in the nasal passages of hoofed mammals. Ew.)
The primate bot fly is a big fly that looks like a bumble bee–not the sort of thing you’d let fly up and lay eggs on you. How do the maggots get in you, then?
The female bot fly sneakily grabs a mosquito and glues 10 or more bot fly eggs onto her. When the mosquito lands on you for a drink, the warmth of your body stimulates the eggs to hatch and the larva to drop down onto you. And gosh, there’s a convenient hole from the mosquito pre-drilled for the maggot!
About 5-10 weeks later, the maggot burrows into the ground, pupates, and eventually emerges as an adult bot fly. And yes, that does mean you’d have flies in you, under your skin, for over a month.
Several entomologists I know who were infested saw this as an opportunity to expand their insect collection, and let some of the flies grow until they emerged. None of them reported serious pain, although they definitely said it wasn’t comfortable, especially when they were trying to get some sleep.
I’m going to Central America–how do I avoid bot flies?
How do you get rid of bot flies?
It’s best if you have a doctor remove them. There’s a risk of infection if you tear or damage the maggot during removal. There are a few other methods you can do yourself; you can read a scholarly article about myiasis, or infection of humans with maggots, here that will detail some of them. (and have more gross photos!)
[edited 9/9/09 to add: rats! that journal article is gone. Here's the citation: Boggild AK, Keystone JS, Kain KC. Furuncular myiasis: a simple and rapid method for extraction of intact Dermatobia hominis larvae. Clin Infect Dis. 2002.]
NOT FOR THE SQUEAMISH: