Sep 26, 2008


Those of you who enjoyed my previous bot fly posts will love this next one. Megan is a biology student who is earning her keep at a veterinary clinic. About a month ago she had to deal with a rash of cuterebra cases in dogs.

Cuterebras are but one iteration of the bot fly. What's a bot fly?

Photo source: Brittanica
Well, the fly itself is harmless. They don't bite or sting. They do vaguely resemble bees, but they have nothing, ecologically speaking, in common with them. You see, a bot fly (a cuterebra in this case), lays its eggs along the paths or around the dens frequented by small mammals (dogs, cats, squirrels, rabbits, etc.). The hapless animals then either rub up against or ingest the eggs, which then hatch. The newly spawned bot fly larvae travel to a spot just beneath the skin and form a 'nodule'.

These nodules can be sizeable, since the larvae which inhabit them can get upwards of two-inches long. The larvae have cutting teeth that they use to cut a little hole on the outside so they can breathe. Look up 'bot fly' on YouTube for videos of them in people's backs. You won't be the same afterwards.

Photo source: unknown

If you find a squirrel with cuterebra nodules, don't worry. The larvae will drop out within 30 days and pupate on the ground. The nodule will heal up. You might not be so cavalier, though, if you get infected. If you do, you'll want to cover the hole with petroleum jelly, which will cause the larvae to emerge for fresh air. Then you can grab it with tweezers. But don't squeeze too hard. If it pops or crumbles inside your skin, it can trigger an infection or even anaphylactic shock.

Ugly, people. Ugly. Thanks, Megan.


Thistle said...

...congratulations. Something on this site finally grossed me out D:

BUH! *shudder*

Anonymous said...

AHHHHH!!! Is human infection *that* common? I don't want to accidentally pop a worm inside my skin!

Anonymous said...

Dear Wombat,
I don't know what makes me religiously and trustingly click on links you provide or go to YouTube and look up bot fly. But I do, knowing full well that such implications may lead to my traumatization.

The story of Kyle in Panama was so terrible, I am now constantly itching and poking my skin. How do they know they get all the larvae out? What if they lay more eggs and they swim around in his bloodstream and one day he's just going along and all of a sudden explodes into a mass of larvae? Those holes in his back were HUGE.

Anyway, I'm sure there will be nightmares tonight and me waking up throwing the blankets off scratching, thinking I'm covered with these things.

Thank you for enhancing my creativity and imagination.

Your friend,

W. A. Whipple said...

I am actually nauseous. I survived Mrs. Anderson's biology class, advanced biology (cat dissection), and *more* adv. bio. - and I never batted an eye. THIS creeped me out, and I didn't even go see the vids, and you can't make me.


Raging Wombat said...

Niner, at least you know what you're getting into when you go in. I hope I've garnered enough trust for that much. You'll notice that I have never rick-rolled anyone.

Anonymous said...

Pookers, my childhood rabbit, had a couple of these. The first one was easily removed by the vet. He was still restless, and in the middle of the night we realized why. There was a second one in his face, pulsing. Even the vet was disgusted removing it. (Pookers was fine, though lost sight in one eye)

Anonymous said...

No, Wombat, you have never misled anyone. I choose, which is my folly.

To Affreca: was the loss of eyesight a direct relation to the larvae? How sad, poor bunny. Wonder what kind of brain damage they do to humans with those stuck in their head.

Sorry for so many posts. Feel chatty today.

Raging Wombat said...

Niner, never apologize for too many comments.

Anonymous said...

Okay, ugh. Just... ugh. I'd rather play with my spiders and bugs. And my dogs. No wonder I'm constantly going outside in the morning and smacking at the flies sleeping on the side of the house.

Just... ugh.

Katie said...

I should know better. I see the words "bot fly", and KNOW what's coming, and yet I keep reading. I really must hate myself.

Anonymous said...

*shudder* I actually went to youtube and looked those up. Blech, I nearly threw up. :( Ew.
Also, thanks for not posting more graphic pictures, I probably would have barfed all over the computer.
(Although the words alone made me ill.)

Anonymous said...

Ugh.. bot flies.... evil insects of my nightmares!!!
I will NEVER go anywhere where these things are. NEVER. Before I knew what a botfly was, I used to have nightmares about worms under my skin. Then I learned of them (thanks internet!).... and just ugh... nightmare come true! Next, I'll be reading that the dead is coming back to life and my hell on earth can begin! Zombies covered with botfly eggs ready to eat me!

Anonymous said...

Niner - I suspect the fly damaged the optic nerve somehow. Pookers lived a good life. We had a fenced in yard that he got to run around in during the day and pretend that he was a wild rabbit (not to likely with his long angora fur). We learned to approach him on his good side, so he wasn't as spooked. He died several years later of old age.

Anonymous said...

I've gone to youtube and looked at these before...maybe some sick humor in me keeps me going back to show new people I meet the horrible videos. I just think everyone's reactions are so funny! I almost vommitted when I first watched them.

Also, I read a story about a guy who had one...down below...

Yeah. Think about that one for a sec.


Anonymous said...

Three types of bot flies infect horses, and cause serious problems. They glue their eggs to a horse, and when they hatch enter the horse's mouth then eventually go into the gastrointestinal track, where they can cause great damage. If you own horses, it's a constant battle to scrape the eggs off of them during summer months, and keep the horses wormed. And to make it more fun... you can pet a horse and transfer bot eggs to yourself and the eggs WILL hatch in YOUR mouth and burrow into the soft tissue of the inner lips or cheeks (and then die a few days afterwards). ICK!

Unknown said...

hey, just wanted you all to know that i just performed home surgery on two of my cats with these disgusting things. No i did not do it with myself. I had a great amount of help from my mom who's an RN, my dad, who's good with some form of animal psychology, and my friend who has a long history with animals. Sure we're not the most qualified bunch but, I gotta say, we pulled it together very nicely. Looking at the directions under the picture of the larvae, i notice the only trouble i ran into was the pulling out part. You actually do have to squeeze pretty dang hard. I used tweezers. My cats weren't happy during this. I'm sure it's uncomfortable for them to have a living, trying to breathe, moving parasite inside of them. Here's a rundown of how we did it.
Step 1: cover the hole with Vaseline, I mean cover the hell out of that thing. Smother it.
Step 2: Wait for the head to pop out.
Step 3: Wait some more
Step 4...

Step 77: When the head finally pops out, do a surprise attack with your tweezers. Have the tweezers already there so you can't miss. Now admittedly, I did miss the first attempt on the second cat but, the second attempt i nailed it. Then it slipped. On the third time I grabbed that things head and briskly but not quickly, took that thing right out of there and then threw it on the ground. My dad then threw it in the fire.
Step 78: Now that you have done all of this it's time to clean the cat. (A paper towel works really nicely) You have to squeeze all that puss out. If you have a heart you will be hurt by this. Maybe. Start at the end of the tunnel and work a finger up the wound. Clean the puss up with the paper towel. Repeat until puss is out. Then get some Beta dine cream and put it over the wound. Try to get it inside the wound too. Then cover it up with Vaseline. Then you have a clean cat. If you have any questions e-mail me at

Raging Wombat said...

Amazing, jfrizzlerizzle. You're a good cat owner.

Anonymous said...

I just pulled one of these out of my dog.... irradiation gross and my dog is scared of me now but its better to have it out than in