Feline Cuterebrosis (Warbles)

Kitten with a Warble

Kitten with a warble.

Recently, a cat was brought into our clinic with a cyst-like protrusion on its chest. Examination revealed it to be Feline Cuterebrosis, also called “Warbles”, a condition in which fly larvae live in the flesh of cats.

What is Feline Cuterebrosis?

Feline Cuterebrosis is a condition occurring when a cat has become the host of the larval stage of the Cuterebra Fly, commonly known as the Botfly.

There are twenty-six known species of the Botfly (Cuterebra) in the United States and Canada.

This condition is often called “Warbles” because the larvae create a burrow with a breathing hole just under the skin causing a lump on the surface of the skin. These lumps are called “warbles”, hence the name.

Feline Cuterebrosis (Warbles) - Botfly or Cuterebra Fly

The Cuterebra Fly, commonly known as Botfly.

Warbles are usually found under the skin in areas around the legs and neck. Cuterebrosis is most commonly found in rodents and rabbits, but have also been reported on cats, dogs, hogs, mink, foxes, deer, cattle, and humans.

What Causes Feline Cuterebrosis ?

Cuterebrosis is a condition most commonly found in wild rodents and rabbits. This condition is caused by the larvae of the Cuterebra fly, which also known as the botfly.

Feline Cuterebrosis (Warbles) Botfly Larva

This is the larva that Dr. Smith removed from the cat’s neck.

The female botfly, genus Cuterebura, lays eggs along the runways and burrow entrances of rabbits and small rodents. The eggs hatch and turn into larvae which enter the unsuspecting host through a natural body opening (usually the nose or mouth) or a small abrasion on the skin.

The larvae will often remain in an animal’s the nose or mouth for several days before burrowing under the skin where they develop into “warbles”. (“Warbles” is the name given to the small lumps produced by growing larvae.) The larvae live and grow just under the skin inside the “warbles”, where they breathe and excrete.

Cats most likely contract Cuterebrosis  by coming in contact with the newly hatched and unsettled larvae from rodents caught hunting, or from  activity around rodent burrows and runways.

Most cats are asymptomatic in the early stages of Feline Cuterebrosis, but sometimes migrating larva can sometimes cause eye problems, nervous system symptoms, and respiratory issues as they move through these systems.

Feline Cuterebrosis (Warbles)

This is the hole left in the cat’s neck after Dr. Smith removed the larva.

How is Feline Cuterebrosis (Warbles) Treated?

Feline Cuterebrosis is treated by carefully removing the larvae and thorough cleaning of the area involved.

Often the cat will be given antibiotics or an antibiotic injection to treat any possible or already occurring secondary infection.

This particular procedure was done under anesthesia and the cat was given an antibiotic injection to treat and prevent secondary infection.



Becki Baumgartner, Practice Manager (89 Posts)

Becki Baumgartner runs the Natchez Trace Veterinary Services Nashville clinic. She is training to become a Certified Master Herbalist, has a BS in Natural Health, is a member of the Nashville Medical Reserve Corps and an Academy of Integrated Health & Medicine Certified Practitioner. Becki also teaches Reiki and Herbology continuing education classes in Nashville and surrounding areas. Natchez Trace Veterinary Services offers a full range of veterinary services from cutting-edge Western medical treatments combined with alternative treatments, herbal formulas, and holistic options that many pet owners cannot find anywhere else. Becki utilizes her natural health and herbal experience, skills, and knowledge to help pet owners understand all of the holistic, alternative, herbal, and standard options options available and achieve and maintain optimum health for their pets. Chat with Becki on Google+ | LinkedIn | Facebook

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  1. sleepyjean1979 says:

    I have encountered this larva in a 6wk old kitten in the sinus cavity with the breathing hole near the inner corner of the eye. I squeezed not knowing this worm like creature would pop out with some force and speed. This kitten could not walk correctly and died within days of the removal. That was in year 2012. Does anyone know how long these warbles have been in the Tennessee area?

  2. ellita says:

    So I got stuck with this kitten. 8 weeks old approx. I live in a rural part of cumberland county tn. Folks like to pitch their unwanted kittens around me smh. I removed said bot fly thing out of its neck. Used hydrogen peroxide and neosporin. As this isn’t my pet I do not have money for a vet and we like to kill kittens at the local shelter. Now it’s been a few days. He has come to life. But the breathing hole is closed up and it’s hard under and around the hole. Like a knot. Should I reopen the scab to loom for signs of infection bc years ago when my actual cat got one in his cheek I took him to the vet I don’t recall the sore being hard but can’t remember bc it was a decade ago. I don’t want this thing to die but he’s acting so much better. 1000% difference almost immediately upon removing the worm. Have a pic of the worm and can take one of his neck now. He possibly also has internal worms and im battling fleas as well with his tiny butt

  3. Stacy Elizabeth says:

    Dr. Smith,

    I pay very close attention to my one year old cat, Mira. She is strictly indoors and we live in a flea-free environment. Though she loves to chase down and eats any bugs that slip inside, we live in a rodent-free house. Despite that, tor the past two days, I noticed her acting funny when she laid down with me to take a nap. She kept trying to bury her face in the bed and kicking me with her hind legs instead of sleeping like a log. Then today I come home from work and notice a large-ish, pink cyst behind her right ear. The fur on this cyst has completely fallen off and though there is no open wound, there is a something like a subcutaneous blood blister near the surface and the cyst itself is firm to the touch. Other than rubbing her face against the carpet and this rather gross and concerning cyst, she seems fine otherwise. I emailed my regular vet and included images of Mira’s cyst and then I called the emergency vet since it is a weekend and after hours; they told me not to panic and just to keep an eye on it for changes. However, I am still panicking and worrying that this could somehow be a warble. Until I hear back from my normal vet, should I apply Neosporin in case it is an ingrown hair or something else? Is it safe to wait a day to take her to the vet’s office or do I need to take her to the emergency clinic? Any advice and help is greatly appreciated. I’m very worried she will develop an infection from this.

    Thank You,

    Stacy Elizabeth

    • This spot could be trauma, an eosinophilic plaque, ringworm or warble. I don’t think its an emergency. Try the neosporin and time and if no resolution in a week or two, then head to your vet.

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