Cuterebra are large North American bot fly larvae that occasionally infest pet rabbits, especially those housed outdoors in summer. The larva burrows into the skin and creates a swollen lump with a small breathing pore. Removal must be done by a vet — squeezing the lump can rupture the larva and trigger a severe inflammatory or anaphylactic reaction. Per AEMV Pet Care Guides, 2024, prompt veterinary removal is the standard of care.
Last reviewed: May 2026
What a Cuterebra Warble Looks Like
A Cuterebra warble in a rabbit appears as a 1- to 3-centimeter firm swelling under the skin, usually around the head, neck, chest, or groin. The diagnostic feature is a small round breathing pore (about 1 to 3 millimeters) at the top of the swelling — the larva uses it to exchange air. Brown or clear discharge sometimes leaks from the pore. The larva itself is plump, off-white to grayish, with rows of dark spines visible if the lump is opened. Most warbles develop 1 to 4 weeks after the rabbit was exposed to a fly-laid egg outdoors. Indoor-only rabbits almost never get Cuterebra unless wild rodents enter the home.
Why You Should Never Squeeze It
Squeezing a Cuterebra warble at home is the single most common mistake. Two bad outcomes follow: the larva ruptures inside the wound, releasing antigenic body contents that trigger severe local inflammation, abscess, or rarely anaphylaxis; or the larva is partially expelled and the remaining pieces become a chronic, painful abscess. A 2008 review of exotic pet parasitology notes that larvae must be removed intact, ideally under sedation, with the breathing pore enlarged surgically to extract the larva whole (Jenkins, 2008, Vet Clinics NA Exotic).
How Vets Remove a Warble
Removal is typically done under brief sedation or local anesthesia. The vet enlarges the breathing pore with a small incision, grasps the larva at the head end with hemostats, and gently extracts it. The cavity is flushed with sterile saline, and most rabbits go home with 5 to 7 days of oral antibiotics, NSAIDs for pain, and once-daily wound flushing. Healing takes 10 to 21 days. Severe cases — multiple warbles, secondary abscess, or larvae near the eye, nose, or throat — may need surgical debridement and a longer course of meloxicam.
Risk Factors
Outdoor-housed rabbits in North America (especially the eastern and southern United States) from May through October are at highest risk. Wild rabbits and rodents are the natural Cuterebra hosts; pet rabbits become accidental hosts when they explore brush or grass where a fly egg attached to vegetation. Risk is highest in: rural or wooded areas, rabbits in hutches accessible to wild rodents, summer-only outdoor playtime without screened enclosures.
Distinguishing Warbles from Other Lumps
Several rabbit conditions can look similar at first glance. Abscesses (very common in rabbits, often from dental disease or bite wounds) are firm to soft and lack a breathing pore. Lipomas are soft, mobile, and not painful. Tumors are usually slower-growing and lack the central pore. Flystrike (myiasis) involves many small maggots on damp soiled skin, not a single deep lump. If unsure, take a clear close-up photo and call the vet — never probe or squeeze.
When to See a Vet
Call your vet today if:
- A new firm lump with a small visible hole at the top
- Brown or clear discharge from a small skin pore
- The rabbit is grooming or scratching one spot persistently
- Visible movement under the skin near a swelling
- A young or outdoor rabbit with any new head, neck, or chest swelling in summer
Go to the ER immediately if:
- Sudden facial swelling, hives, or labored breathing after attempted home removal
- Severe weakness, pale gums, or collapse
- A warble located very close to the eye, nostril, or mouth with respiratory difficulty
- Profuse bleeding from the lump
- The rabbit has stopped eating for more than 12 hours (any rabbit anorexia is an emergency)
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Frequently Asked Questions
How much does Cuterebra removal cost in a rabbit?
A straightforward removal with sedation, surgical pore enlargement, flush, and 5 to 7 days of oral antibiotics and pain medication typically costs $200 to $500 at a general practice and $400 to $800 at an exotic specialist. Cases with secondary abscess, multiple warbles, or near-eye involvement can run $500 to $1,500 with imaging and extended care. Exotic-experienced vets are recommended; rabbits metabolize many drugs differently than dogs and cats.
Can a Cuterebra warble kill a rabbit?
It can, indirectly. The larva itself rarely kills, but a ruptured larva can trigger systemic inflammatory response or severe abscess. More commonly, the stress of infestation triggers GI stasis — a rabbit emergency that is itself fatal within 1 to 2 days if not treated. Any rabbit who stops eating after a skin issue needs urgent vet care.
Can I prevent warbles?
Yes. Keep your rabbit indoors or in a fully screened enclosure during fly season (May through October). Eliminate brush and rodent harborage near outdoor housing. Inspect the rabbit's skin daily during summer — early lumps are easier to remove. Topical fly repellents marketed for rabbits are limited; mechanical exclusion is the most reliable prevention.
How is a warble different from flystrike?
Flystrike (myiasis) is a different problem caused by blowfly maggots that hatch on a damp, soiled, or wounded area of skin — usually around the tail or back end. Maggots are smaller, more numerous, and visible crawling on the skin within hours. Flystrike is a true emergency requiring same-day treatment. Cuterebra is a single, deeper larva with a slower onset and a single breathing pore.
Will the warble come back after removal?
The same larva does not return once removed intact. Re-infestation can occur if the rabbit is exposed to more Cuterebra eggs the next season. Treat the environment (rodent control, screened housing) to reduce future risk.
Still Not Sure if Your Rabbit Needs a Vet?
When you're not sure if this is wait-and-see or call-tonight, Voyage AI Vet triages in under 2 minutes. Describe what you're seeing in chat, share photos of the lump, the small breathing hole at its center, and any discharge — close-up with good lighting, or hop on a live video call if you want a second pair of eyes. Every answer comes with citations to the actual veterinary literature it's pulling from — so you see exactly where the guidance comes from, not just a chatbot's word.