Myxomatosis: a dreadful disease that’s about to start all over again
“Myxie” rabbits are a sad feature of many a grass verge at this time of year as they wander, seemingly unaware of the obvious dangers they are in. The myxoma virus which causes this dreadful disease only infects rabbits. The disease causes disfiguring skin swellings, particularly noticeable around the face and eyes, a high fever and anorexia. Complications, including pneumonia commonly occur in affected individuals. Unfortunately there is no specific treatment and a slow lingering death typically results. It can take as little as 2 weeks from the time a rabbit acquires an infection for the full horror of the disease to become apparent. Rabbits can sometimes recover from the condition following very intensive nursing, but most are unable to cope. Sadly euthanasia is usually the most humane option available.
The risk to pet rabbits
It is often assumed that pet rabbits are less likely to be affected, but the typical veterinary centre caseload from August to November tells a very different story and many thousands of rabbits are seen annually by Veterinary Centres throughout the country. Whilst close contact can spread the disease between rabbits, external parasites such as fleas, mites and biting flies are particularly important in transmitting the virus. This means that all pet rabbits are at risk from infection, even household rabbits. Additionally, cats often become infected with rabbit fleas and will bring these in to your garden or inside your house.
The tendency for higher average temperatures in recent years, particularly during the winter months means that the parasites which carry the virus survive for longer. As a result myxomatosis cases are being reported outside the normal high-risk period and even in the depths of winter.
Protection is the only safeguard
Since treatment almost always fails, even with the greatest nursing efforts, the main aim is to try and prevent infection in the first place - and that means vaccination. Rabbits can be vaccinated from as young as six weeks of age. The vaccine contains a harmless virus which is similar to the myxoma virus and gives the immune system a head-start in fighting myxomatosis if exposed. The vaccine is given by injection, usually into the scruff at the back of the neck. Sometimes a rabbit may seem ‘off colour’ for a day or two after his vaccination and the injection site may also become tender or swollen for a short period.
Vaccination will need to be repeated regularly to maintain the protection against the disease. Usually a good level of protection can be achieved with six monthly injections. It used to be felt that protection could be maintained with just a yearly booster injection. This approach has now been abandoned since the problem is a year round one, and targeting the worst period of the year - the autumn and winter seasons - just isn’t protection enough.
Occasionally a rabbit may not be fully protected against myxomatosis, even after vaccination. This may be because the rabbit was already ill or stressed when it was vaccinated and its immune system wasn’t working properly. It’s for this reason that a full health examination is made before vaccination to try and detect such rabbits. If there are any signs of illness seen then vaccination is delayed until your rabbit is well again. At the health examination fleas and mites are also looked for. It is important to reduce the chance of exposure to the virus by recognising, treating and preventing flea and mite infestations. Spotting these problems is advised on at the health check. Fly control is also important. As well as biting flies that may cause a rabbit to contract myxomatosis, blow flies can lay eggs around the rabbit’s hindquarters leading to maggot infestation (also known as “fly-strike”). Using insecticidal fly-strips in the vicinity of the hutch or run outside the reach of your rabbit and, where appropriate, the use of fine-netting or screens should reduce the risk of your rabbit encountering flies. Strict attendance to hutch hygiene and twice-daily checking of your rabbit for faeces matted in the fur around the hind quarters will also help to reduce the attraction of flies.
© copywrite Dai Gittins MRCVS.
