Rabbit Myxomatosis Emergency Signs: Swollen Eyes, Breathing Trouble, and Sudden Death
Introduction
See your vet immediately if your rabbit has suddenly swollen eyelids, eye or nose discharge, trouble breathing, marked lethargy, or stops eating. Myxomatosis is a severe viral disease of rabbits that can worsen over hours to days, and some rabbits die suddenly before many signs are obvious. In pet rabbits, the disease is often fatal, so fast veterinary assessment matters for comfort, isolation, and next-step planning.
Early signs can look subtle at first. A rabbit may develop puffy, red eyelids, drooping ears, swelling around the face or genitals, fever, or thick eye discharge. As the illness progresses, breathing can become labored, appetite can drop, and secondary infections such as pneumonia or septicemia may develop. Rabbits are prey animals and often hide illness, so even mild swelling around the eyes should be taken seriously.
Myxomatosis is usually spread by biting insects such as mosquitoes, fleas, and flies, though direct contact with infected rabbits or contaminated items may also spread the virus. Outdoor exposure raises risk, but indoor rabbits are not fully protected if insects can get inside. In parts of the western United States, including California and Oregon, cases have been reported, and a 2024 JAVMA study of 11 pet rabbits in California found bilateral eyelid swelling in every case and sudden death in 4 of 11 rabbits.
This guide is here to help you recognize an emergency and prepare for the visit. It cannot diagnose your rabbit at home. If you suspect myxomatosis, keep your rabbit calm, separate them from other rabbits, and call your vet or an emergency clinic right away.
Why myxomatosis is an emergency
Myxomatosis is caused by the myxoma virus, a poxvirus that causes severe disease in domestic European rabbits. Published veterinary references describe very high mortality, and US sources note that there is no reliably effective curative treatment once infection is established. That is why the goal of emergency care is often rapid diagnosis support, isolation, comfort care, and a realistic discussion with your vet about prognosis and options.
The disease can move quickly. Veterinary sources describe peracute cases that may lead to death within about a week of exposure, while other rabbits survive one to two weeks with progressive swelling, discharge, fever, and breathing difficulty. Because rabbits can decline fast, waiting overnight to "see how things go" can remove options for supportive care and humane decision-making.
Emergency signs pet parents may notice at home
- Puffy, swollen, or red eyelids
- Thick eye discharge or conjunctivitis
- Swelling around the ears, nose, lips, or genitals
- Ear droop or a suddenly different facial appearance
- Fever, marked lethargy, or hiding more than usual
- Refusing food, fewer droppings, or not drinking
- Noisy, rapid, or labored breathing
- Open-mouth breathing, stretched neck posture, or blue-tinged gums or tongue
- Sudden collapse or sudden death
Breathing trouble is especially urgent. Merck notes that trouble breathing in rabbits warrants immediate veterinary contact, and rabbit emergency resources consistently treat open-mouth or labored breathing as a true emergency. Handle your rabbit as little as possible, keep them cool and quiet, and head to your vet right away.
What your vet may do
Your vet will usually start with a hands-on exam, temperature check, and assessment of breathing effort, hydration, pain, and appetite. Diagnosis is often based on the pattern of signs and exposure history, then supported with testing such as blood work and PCR on tissue or skin samples when available. Because myxomatosis can resemble other serious rabbit illnesses, your vet may also consider differentials such as severe bacterial infection, trauma, allergic swelling, or rabbit hemorrhagic disease.
Treatment options depend on how sick the rabbit is and what is realistic for the family. Supportive care may include oxygen support, fluids, assisted feeding, pain control, anti-inflammatory medication, and antibiotics for secondary bacterial infection when indicated by your vet. In many cases, humane euthanasia is discussed because suffering can be significant and prognosis is often poor.
What to do on the way to the clinic
Keep your rabbit in a secure carrier lined with a towel. Minimize stress, noise, and handling. Do not force food or water into a rabbit that is struggling to breathe, because aspiration is a risk. If you have other rabbits at home, isolate the sick rabbit and wash your hands after contact.
If your rabbit recently spent time outdoors, had insect exposure, or had contact with wild rabbits or a rabbit who was ill, tell your vet. Those details can help your vet assess risk quickly. If your rabbit dies suddenly and myxomatosis is a concern, call your vet before disposing of the body so they can advise you on safe handling and possible reporting steps.
Prevention and household risk reduction
Prevention focuses on reducing exposure. Keeping rabbits indoors, using intact window screens, controlling mosquitoes and fleas, and avoiding contact with wild rabbits all lower risk. VCA notes that a myxomatosis vaccine is not available in the United States, so environmental prevention is especially important for US pet parents.
Outdoor time is not automatically wrong, but it changes risk. In endemic areas, screened housing and insect control matter. Ask your vet what prevention steps make sense for your rabbit's location, lifestyle, and season.
Questions to Ask Your Vet
Bring these questions to your vet appointment to get the most out of your visit.
- Based on my rabbit’s signs and location, how concerned are you about myxomatosis versus other emergencies?
- Does my rabbit need immediate oxygen support, hospitalization, or isolation from other rabbits?
- What tests would help most today, and which ones are optional if we need a more conservative plan?
- What supportive care options are available for breathing trouble, dehydration, pain, and not eating?
- What is the expected prognosis in my rabbit’s case, and what signs would mean quality of life is too poor?
- If treatment is attempted, what monitoring will my rabbit need over the next 24 to 72 hours?
- What cost range should I expect for outpatient care versus hospitalization?
- How should I protect my other rabbits and clean the environment at home?