Cuterebra are not cute (and maggots are just plain gross)

Parasites create a buzz of excitement in a veterinary clinic. Creepy, crawly, stinky? Bring it on!

This week was especially interesting with the appearance of two different species of parasitic larvae arriving inside the skin of two of my mammal patients. The technical term for parasitic fly larvae is "myiasis."

Rabbit afflicted with Cuterebra larva

First, a father called worried that his daughter's pet bunny had been shot with a B-B gun while it was in its outside enclosure because it had a hole on either side of its neck. When the bunny arrived she was bright and alert. Although she had two large wounds on her neck that were leaking fluid and pus, I learned she was not acting sick at home. As I prodded one of Flopsy's wounds a little maggot head peeked out at me! "Cuterebra!" I exclaimed happily.

While disgusting, cuterebriasis is a common and treatable condition in rabbits. Sometimes these larvae show up in the skin of kittens, cats and dogs as well. In the spring and early summer the female Cuterebra fly lays her eggs on blades of grass. When a rabbit or other mammal brushes against the infected grass, the egg or a recently hatched maggot attaches to its fur and then eventually burrows under the skin where it sets up shop. Occasionally these maggots migrate to the wrong place (like the lungs or brain) and cause all sorts of problems, but usually they mature into grubs inside their "warble" under the skin. Eventually they drop off the animal back into the soil where they finish developing. The B-B sized holes seen on Flopsy are the grubs' tell-tale breathing holes.

Removing Cuterebra larva from its warble under the skin

I very carefully removed a pair of fat Cuterebra grubs from Flopsy's neck, cleaned the wounds and started her on an antibiotic for the secondary bacterial infection in her skin. While removing Cuterebra larvae, care must be taken not to break or rupture the grub inside the skin because the pieces will cause festering wounds.*

I know it may be a matter of personal preference, but I find that while Cuterebra are not cute, they are definitely not as disgusting as regular old maggots. Our second myiasis patient, Trina, was an obese outdoor kitty who came in crawling with maggots. Trina had a terrible skin infection around her vulva (she couldn't clean herself because she was so obese) and a ruptured anal gland abscess. Flies had been attracted to her stinky, moist, dying flesh and had laid eggs there. We pulled dozens of wriggling white maggots from Trina's skin, inside her vulva and surrounding fur. (Yes, it was gross even for us veteran parasite handlers.) Then we shaved off the nasty matted fur on her back end, cleaned her wounds and administered pain medication and antibiotics. By the time we finished Trina looked, smelled and felt a million times better. Once we get her through this rough patch, Trina's family and I will be working together to get the extra Lbs off her.

*One theory behind the medical and veterinary symbols of a "snake" wrapped around a staff may stem from a skin parasite in people called Guinea Worm (dracunculus medinensis).  A traditional method of treatment is to wrap the end of worm around a small stick, gradually and carefully twisting the stick until the worm is completely extracted from the person's skin. Breaking the worm inside the skin can create a life-threatening bacterial infection such as tetanus.