Rabbit myxomatosis: symptoms, progression and vaccination

Veterinary warning — Myxomatosis is a veterinary emergency. A rabbit with swelling of the face, eyelids, or genitals should be examined as an emergency. This guide is informational and does not replace a veterinary consultation.

Myxomatosis is one of the most feared diseases for rabbit owners. Caused by a poxvirus (Myxoma virus), it is endemic throughout Europe and can affect any domestic rabbit — including a house rabbit that never goes outdoors. Without vaccination, death occurs in more than 95% of cases in the acute form. Knowing the symptoms and understanding why preventive vaccination is essential can literally save your rabbit’s life.

The virus and its origin

Myxoma virus belongs to the family Poxviridae. It was deliberately introduced into France in 1952 to control wild rabbit populations that were destroying crops — with devastating consequences for wild and domestic rabbit populations alike. Today, myxomatosis is endemic throughout Western Europe. Attenuated strains have naturally emerged over the decades alongside highly virulent strains.

Routes of transmission

Myxomatosis spreads primarily through insect vectors:

• Fleas: the rabbit flea (Spilopsyllus cuniculi) is the most efficient vector; cat and dog fleas can also carry the virus
• Mosquitoes: transmission via mosquitoes explains why the disease peaks in summer and autumn
• Other biting insects: mites, lice, flies

The virus can also spread through direct contact between a sick and a healthy rabbit, or via contaminated objects (cage, accessories, the owner’s hands).

An indoor rabbit that never goes outside is not safe: mosquitoes enter through open windows, and fleas can be brought in by other pets or on the owner’s clothing.

Symptoms by clinical form

Acute form (most common, most lethal)

The incubation period is 3–14 days. Signs then appear rapidly:

Early stage (days 1–3 after first signs):

• Swelling of the eyelids (oedematous blepharitis) — often the first visible sign
• Bilateral purulent eye discharge
• Swollen muzzle and nose
• Mild fever, lethargy

Intermediate stage (days 3–7):

• Swelling extending to the face, ears, and genitals (vulva or scrotum)
• Cutaneous nodules (myxomas) appearing on the body
• Increasing breathing difficulties (associated bronchopneumonia is common)
• Refusal to eat, prostration

Terminal stage:

• Inability to open eyes, laboured breathing
• Death typically occurring between days 8 and 15

Attenuated form (less virulent strains)

Since the 1960s, attenuated strains have been circulating in Europe. They cause:

• Nodular cutaneous myxomas without the major facial oedema
• A slower progression
• Reduced mortality (approximately 30–50%) but still high in unvaccinated rabbits
• Possible spontaneous recovery with sequelae in some individuals

Respiratory form (variant)

Some strains cause mainly respiratory symptoms (cough, severe rhinitis, pneumonia) with few cutaneous swellings. This presentation can be confused with severe snuffles — see our article on rabbit snuffles to differentiate the two.

Treatment: supportive care only

There is no specific antiviral treatment for myxomatosis. Management is exclusively symptomatic and supportive:

• Fluid therapy (subcutaneous or intravenous rehydration)
• Assisted feeding if the rabbit stops eating (Critical Care syringe feeding)
• Antibiotics to prevent or treat secondary bacterial infections (pneumonia, snuffles)
• Anti-inflammatories and pain relief appropriate for rabbits
• Eye cleaning and maintaining nasal airway patency
• Warmth and calm: keep the rabbit at a stable temperature (20–22°C), away from stress

This supportive treatment can allow some rabbits to survive an attenuated form, but mortality remains high. The decision to treat aggressively or euthanise on humane grounds should be discussed with the vet on a case-by-case basis.

If your rabbit shows signs of myxomatosis, seek emergency veterinary care immediately — every hour matters.

Vaccination: the only real protection

Vaccination against myxomatosis is the only effective means of protection. It is recommended for all rabbits, indoor and outdoor alike, from 5 weeks of age.

Standard vaccination protocol (UK context)

In the UK, two diseases are typically covered simultaneously: myxomatosis and RHD (Rabbit Haemorrhagic Disease, also called VHD). Combined myxomatosis + RHD2 vaccines are available. The recommended schedule:

For full protocol details and vaccine choice, see our guide on rabbit vaccination.

Efficacy and limitations

A correctly vaccinated rabbit can still be infected by certain strains, but will develop a much milder form with a substantially higher survival rate. Vaccination does not guarantee complete protection, but it is radically superior to no protection at all.

Additional prevention

Beyond vaccination:

• Regular antiparasitic treatment (flea prevention) for the rabbit and all other pets in the household
• Window screens during the risk season (spring through autumn)
• Avoid contact with wild rabbits or rabbits of unknown vaccination status
• Quarantine any new rabbit before introducing it to the existing household

For a comprehensive overview of rabbit health needs and routine vet care, visit the rabbit species page.