It is a pox-like viral disease that grows best in skin (particularly soft skin areas) of rabbits. The virus mutates from year to year. Background immunity in wild rabbit population varies. Domestic rabbits have no genetically based immunity.The number and severity of outbreaks varies. There was a particularly severe strain outbreak in 2000.
The greatest risk is to rabbits that live outdoors, in contact with wild rabbits/hares or affected by rabbit fleas. Rabbits in contact with dogs or cats that hunt are also at risk.
Spread by biting insects: infected fleas, mosquitoes and fur mites. Direct rabbit to rabbit spread can occur, but very rarely. Virus can survive over winter in fleas and infected mosquitoes can shelter in hay and houses.
Incubation period: 5 to 14 days.
Signs and Symptoms
- initially runny eyes, swollen genitalia,
- sever conjunctivitis, blindness
- swelling of the head and genital region
- lumps all over the body
- ending in death over a fortnight.
Vaccination cannot guarantee protection against the disease but it offers the best chance of immunity against it. Vaccinated rabbits can still catch myxomatosis but infection is less severe so the rabbit may survive with intensive care and treatment, but may also die from a secondary infection eg pneumonia.
Vaccine: in Britain (Nobi-vac Myxo) is made from a harmless virus that protects by cross immunity (cf cow-pox/small-pox) and has fewer side-effects than live viruses used elsewhere in Europe.
Annual boosters are adequate for animals not at high risk and unless there is a severe outbreak as in 2000. Then 6 monthly boosters are recommended. High risk = low-lying areas with standing water; a large mosquito population and local outbreaks in wild rabbit population. Myxomatosis tends to break out in Autumn so Spring-Summer is optimal time for annual boosters.
Note: vaccine has to be given intradermally (not sub-cutaneously as most other vaccines). Check vet remembers this and if a lay person is vaccinating, check they know the technique.
Vaccination is just one of the measures to be taken to protect pet rabbits from the disease.
Other preventative measures include: acquire hay form myxomatosis-free farms, fit insect screens to hutches, eliminate standing water from garden, keep bedding dry so not attractive to mosquitoes, avoid contact with wild rabbits, control insect parasites, avoid stress which lowers natural immunity.