What Is Cuterebra?
Cuterebra is a genus of botflies found in North America. Their larvae normally live in rabbits and rodents, but cats and dogs can pick them up while exploring burrows or tall grass. The larva enters through the nose, mouth or a small wound, travels under the skin and settles in one spot, where it forms a lump with a small breathing hole. The condition is also called cuterebriasis or a “warble”.
Signs
- A firm swelling, usually on the head, neck or chest
- A small hole in the center of the lump, sometimes with a moving larva visible
- Fluid or discharge from the hole and matted fur around it
- Most cases appear in late summer and early fall
Do not squeeze it out
Crushing or tearing the larva can trigger a severe allergic reaction or infection. Let a vet remove it whole.
How Vets Treat It
- Gently widening the hole and removing the intact larva, often under sedation
- Cleaning and flushing the wound, which then heals as an open wound
- Antibiotics if the area is infected
Wounds left after removal need the same care as other skin wounds; see cat wound care and dog wound care. A warble can look like an abscess at first, which is why a vet check matters.
Rare but serious
Occasionally a larva migrates to the brain, eye or airway instead of the skin. Sudden neurological signs, such as circling or seizures, in late summer in an outdoor cat need urgent attention.
Frequently Asked Questions
Can Cuterebra spread from pet to pet?
No. Pets are infected from the environment where botflies lay eggs, not from each other.
How can I prevent it?
Keep cats indoors and keep dogs away from rabbit and rodent burrows. Some monthly flea and tick products may reduce the risk; ask your vet which is suitable.
Is it painful?
The lump is often not very painful at first, but it can become sore and infected, especially if the larva dies or is damaged.
Groomers often spot a warble first while working through the coat; you can find pet groomers near you, but removal should always be done by a vet.
If you find a lump with a hole in it, do not try to remove it yourself. Find a veterinary clinic near you for an exam.