You’ll Never Guess What Was Living In His Skin.

The bot fly larva.

The botfly larva.

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Eventually, every tropical field biologist gets parasitized. Working in the conditions we do, these parasites can be intestinal, they can cause lesions, or they can bore into your skin and eat your flesh.

Geoff Gallice is an entomologist who, much like I do, works with butterflies in the Amazon rainforests of Southeastern Peru. We’re practically neighbors when we’re in the field, but apparently there is one thing that his region has a lot more of than the Tambopata region where I work: botflies.

The surgery. © Geoff Gallice.

The surgery. Even the doctors are taking pictures. © Geoff Gallice.


As Geoff wrote:

The human botfly, Dermatobia hominis (Oestridae), is a parasite that infects humans, and is found throughout the neotropics. The female uses a mosquito as an intermediary, placing eggs on her underside, which hatch when the mosquito lands on the host to feed. The fly larva subsequently burrows into the skin, where it feeds on interstitial fluid for 8-12 weeks before emerging to pupate.

That’s right. The adult botfly tackles a mosquito, lays eggs on it, and then when the mosquito lands on you the eggs hatch, the larvae jump ship, and start digging (and eating) into your flesh.

About the size of a baby carrot.

About the size of a baby carrot.


As an entomologist I’ll admit I’m jealous. If you’re an entomologist who’s been stung by a bullet ant and been parasitized by a botfly you get some sort of badge, or trophy, or stamp of approval from other entomologists because it is evidence that you’ve done your time in the field, and you seriously know how to rough it. While I have had the pleasure of a bullet ant sting, through all my time in the field I’m still lacking the skin boring parasite I could smile proudly about.

This is Geoff’s fifth botfly, having had four previously from work in Panama in 2011 and he currently has four more inside of him that the doctors are taking out this week. Yikes.

Smile for the camera.

Smile for the camera.


So if this thing is feeding on you, how do you get it out? The trick is that, like most insects, a bot fly larva needs to breathe air. So one method is to suffocate it using vaseline or duct tape, then remove the barrier and grab it as it pokes out for air. Unfortunately for us, all of those black dots along the side of this human-eating maggot are backwards-facing hooks. So as you pull, it digs in to your skin deeper.

The other traditional remedy is to poison it, using either banana skin sap or by blowing tobacco smoke on it. These unfortunately leave you with a dead maggot inside which can be hard to remove. While Geoff used traditional methods of extraction in Panama, these guys were a bit too large so he went the route that I would recommend: to the doctor.

Botflies in humans have been known to confuse American doctors who assume an inflamed, red, painful mosquito bite is just infected and will prescribe antibiotics. So travelers beware, that swollen mosquito bite that hasn’t gone away since your trip to Costa Rica? Could be a botfly. And the entomologist in me is darn jealous.

Coincidentally, I did a piece with Discovery Channel on this very thing, which you can check out here:


2 Comments to "You’ll Never Guess What Was Living In His Skin."

  1. Stephen Landry's Gravatar Stephen Landry
    February 19, 2014 - 10:01 pm | Permalink

    Very interesting article with even better pictures. Thanks !

  2. May 31, 2014 - 4:02 pm | Permalink

    Excellent way of telling, and good article to take data concerning my presentation subject, which i am going to convey in school.

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