Myxomatosis is a poxvirus disease spread mainly by mosquitoes and fleas that causes swollen eyelids, swollen genitals and face, lethargy, and almost universal death in pet European rabbits. Vaccination is available in the UK, EU, and some other countries but not in the US. Suspected cases need immediate isolation from other rabbits and an emergency vet visit; supportive care can occasionally save a vaccinated rabbit but most unvaccinated rabbits die within 10 to 14 days.
Last reviewed: May 2026
How Myxomatosis Spreads
Myxomatosis is caused by the myxoma virus, a poxvirus. Transmission is mainly by biting insects — mosquitoes, rabbit fleas, mites, and lice — which mechanically carry the virus from infected wild rabbits to pet rabbits. Direct rabbit-to-rabbit contact also spreads the virus. Outdoor rabbits and rabbits in mosquito-heavy regions are at the highest risk. Seasonal peaks correspond to mosquito activity in summer and early fall in most temperate climates.
The Classic Clinical Picture
Early signs include swollen eyelids that progress to complete closure, swollen genitals, lethargy, and lumpy raised skin lesions ('myxomas') on the head, ears, and body. Within 5 to 10 days, severe respiratory distress, anorexia, and high fever follow. Death usually occurs within 10 to 14 days in unvaccinated rabbits. Mortality is over 99 percent in unvaccinated pet European rabbits (Oryctolagus cuniculus).
Diagnosis and Differentials
Clinical signs are usually diagnostic in an unvaccinated rabbit in an endemic area. PCR testing of skin lesions confirms when needed. Differentials include severe pasteurella infection, bacterial blepharitis, treponematosis, and trauma. A rabbit with sudden bilateral eyelid swelling in summer should be considered myxomatosis until proven otherwise.
Vaccination Where Available
Combined RHDV2/Myxomatosis vaccines (such as Filavac and Nobivac Myxo-RHD) are widely used in the UK and EU. Primary vaccination at 5 weeks of age plus annual boosters give high protection. In the US, myxomatosis vaccines are not licensed; prevention relies on insect control, indoor housing during peak mosquito season, and biosecurity. Outdoor hutches should be screened with mosquito netting.
Treatment and Prognosis
There is no specific antiviral treatment. Care for vaccinated rabbits showing mild signs is supportive: pain control, fluids, syringe feeding, eye lubrication, and antibiotics for secondary bacterial infection. Per the Benato et al., 2019, JSAP survey on rabbit pain management, aggressive analgesia is essential — meloxicam plus an opioid is standard. Vaccinated rabbits can sometimes recover; unvaccinated rabbits with severe signs almost always die or are humanely euthanized.
Cost of Treatment and Prevention
In the UK/EU, the combined RHDV/Myxomatosis vaccine costs about £40 to £60 ($50 to $80) per year. An exotic-vet exam costs $75 to $200, supportive hospitalization for a sick rabbit runs $500 to $1,500 a day, and PCR testing is $80 to $200. Most severely affected unvaccinated rabbits are euthanized within 24 to 48 hours on welfare grounds. Vaccination prevention costs far less than the emotional and financial cost of an outbreak.
When to See a Vet
Call your vet today if:
- Swollen eyelids, especially both eyes at once
- Lumpy raised skin lesions on head, ears, or genitals
- Lethargy plus reduced appetite in a rabbit with insect exposure
- Recent contact with wild rabbits or known myxomatosis area
- Unvaccinated rabbit with sudden facial swelling
Go to the ER immediately if:
- Severe respiratory distress (mouth breathing, gasping)
- Complete eye closure with discharge and collapse
- Off food and water for more than 12 hours (GI stasis on top of viral disease)
- Multiple rabbits in the household showing signs
- Suspected severe pain (teeth grinding, hunched posture, refusal to move)
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Frequently Asked Questions
Can my indoor-only rabbit get myxomatosis?
Yes, though risk is lower. Mosquitoes get indoors through open windows and screens, and rabbit fleas can be carried in by other pets or owners. Most indoor rabbit cases in endemic areas come from mosquito bites in summer. Vaccination (where available) is still recommended for indoor rabbits.
How much does the myxomatosis vaccine cost?
In the UK, the combined RHDV2/Myxomatosis vaccine (Nobivac Myxo-RHD Plus) is typically £40 to £60 ($50 to $80) per dose at most vet practices. Annual boosters are recommended. Vaccination requires an exotic-vet exam fee of about $75 to $200 each visit. The vaccine is not currently available in the US.
Is myxomatosis painful for the rabbit?
Yes, severely. Skin lesions, swollen mucous membranes, secondary bacterial infections, and high fever cause significant suffering. Aggressive pain control with meloxicam plus opioids is essential when treating, and humane euthanasia is often the most compassionate option for severely affected unvaccinated rabbits.
Can a rabbit who recovers spread the virus to other rabbits?
Yes. Recovered rabbits can shed virus for several weeks. Strict quarantine for at least 4 weeks and thorough disinfection (10 percent bleach, 10-minute contact time) is needed before introducing recovered rabbits back to a multi-rabbit household.
Does the vaccine work right away?
Protective immunity develops 2 to 3 weeks after vaccination. Rabbits vaccinated for the first time should ideally be vaccinated 3 to 4 weeks before mosquito season starts. Annual boosters keep immunity high; some vets recommend 6-monthly boosters in high-risk areas.
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 any facial swelling, eyelid changes, or skin lumps — clear, well-lit photos help us see the pattern, 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.