Myxomatosis is one of the most feared diseases in the rabbit world — and for good reason. This viral disease is nearly always fatal in unvaccinated domestic rabbits, and in 2026 it remains a significant threat to pet rabbits in California, Oregon, and Baja California. Understanding the signs and how to prevent exposure is essential for any rabbit owner in affected regions.
What Is Myxomatosis?
Myxomatosis is caused by Myxoma virus, a poxvirus that was originally introduced to control wild rabbit populations in Australia and parts of Europe. In North America, it circulates primarily among wild brush rabbits (Sylvilagus bachmani) along the West Coast, particularly in California and Oregon.
The virus is transmitted primarily by biting insects — mosquitoes, fleas, mites, and flies — making outdoor rabbits and indoor rabbits with access to gardens at highest risk. Direct contact with infected rabbits can also spread the virus.
There is currently no approved vaccine in the United States, though vaccines are available in Europe and the UK where the disease is more widespread.
Symptoms of Myxomatosis in Rabbits
Symptoms typically appear within 3-5 days of infection and progress rapidly:
- Swollen, puffy eyelids — often the first sign; progresses to complete eye closure
- Nasal discharge and conjunctivitis (pink eye)
- Swelling of the face — lips, nose, ears, and genital area
- Skin nodules or lumps appearing across the body
- High fever and extreme lethargy
- Loss of appetite — rabbits stop eating and drinking
- Difficulty breathing as the disease advances
- Death — typically within 2 weeks of symptom onset in acute cases
If your rabbit shows runny nose or nasal discharge along with facial swelling, seek veterinary attention urgently. Similarly, rabbit eye discharge combined with lethargy and swelling should be treated as a potential emergency.
When to Worry
If you live in California or Oregon and your rabbit develops:
- Any facial swelling, especially around the eyes
- Conjunctivitis (red, weeping eyes) combined with lethargy
- Skin nodules or lumps appearing suddenly
Contact an exotic vet immediately. Even with supportive care, prognosis is poor — but early veterinary intervention can provide palliative comfort.
What to Do at Home (While Getting Help)
- Keep your rabbit indoors away from insects
- Apply mosquito netting to outdoor enclosures
- Use flea prevention recommended for rabbits (never use dog or cat flea products — many are toxic to rabbits)
- Do not allow contact with wild rabbits or their habitat
Supportive care (fluids, syringe feeding, warmth) buys time but does not cure the disease. Most rabbits with full myxomatosis die despite intensive treatment.
Prevention
- Keep rabbits indoors — this is the single most effective preventive measure
- Use insect screens on windows and rabbit areas
- Flea control on all pets in the household
- Avoid outdoor exercise in damp/wooded areas where wild rabbits are present
How Voyage Can Help
Voyage AI Vet can help you assess whether your rabbit's symptoms warrant emergency exotic vet care — starting at $4.99/month. For rabbits in California and Oregon showing signs of myxomatosis, always contact an exotic vet as soon as possible.
Frequently Asked Questions
Q: Is myxomatosis in the US only in California and Oregon? A: In North America, myxomatosis is primarily limited to California, Oregon, and parts of Baja California, where the wild reservoir host (brush rabbit) lives. Isolated cases have occurred elsewhere, but widespread disease follows the wild rabbit range.
Q: Can I vaccinate my rabbit against myxomatosis? A: In the US, there is currently no USDA-approved vaccine. In the UK and Europe, vaccines are widely available. If you import or travel with rabbits internationally, discuss vaccination with your exotic vet.
Q: Can myxomatosis spread to other pets or humans? A: No. Myxoma virus is specific to rabbits — it cannot infect dogs, cats, birds, or humans.
Q: Can a rabbit survive myxomatosis? A: Rarely, with intensive supportive care, some rabbits survive if they develop a milder chronic form of the disease. However, acute myxomatosis in domestic rabbits carries a mortality rate approaching 99%. Euthanasia is sometimes recommended to prevent suffering.
Q: Should I keep my rabbit indoors if I live in California? A: Yes, strongly. Indoor rabbits with no outdoor access or insect exposure have a very low risk of contracting myxomatosis.
This article is for informational purposes only and is not a substitute for professional veterinary advice. For exotic pets, always consult a vet with exotic animal experience.