Infectious Diseases of Rabbits

Myxomatosis

This is caused by the Myxoma virus which is widely distributed in the wild rabbit population. You might argue that your rabbit never comes into direct contact with animals from the wild and so does not need protection. The problem is that the virus is carried by rabbit fleas and mosquitoes so the disease can be passed on without direct contact. The incubation period is two days to a week and the first sign is the development of puffy eyelids and a purulent (pus-producing) conjunctivitis. Swelling under the skin extends around the eyes, ears and genital region. Death is usually 18 days to three weeks after infection but occasionally animals will survive and signs regress over three months. 

A milder form may be seen in partially immune rabbits. In these the signs are solid masses. They often appear as lumps over the ears and head. They may be single or multiple. In some cases lumps may appear on the rest of the body. With proper nursing they will normally survive but the masses may take over six months to disappear.

Unfortunately, although a myxomatosis vaccine is available overseas, it is not currently available in Australia.

Viral haemorrhagic disease

This was first noticed in China many years ago but now has an almost world-wide distribution and is seen more and more in the UK. Viral haemorrhagic disease is caused by a calicivirus and, although the incubation period is up to three days, animals may die suddenly without any clinical signs. If there are signs they include anorexia (not eating), pyrexia (fever) apathy and prostration. There may be convulsions and coma, dyspnoea (difficulty breathing), a mucoid foaming at the mouth or a bloody nasal discharge. Some animals survive this acute phase but die a few weeks later of liver disease and jaundice.

"Viral haemorrhagic disease is caused by a calicivirus and, although the incubation period is up to three days, animals may die suddenly without any clinical signs."

Given the horrendous death experienced by affected rabbits, every rabbit should be vaccinated annually.

In Australia a vaccine is available Cylap (Zoetis) which contains inactivated haemorrhagic disease virus (VHD). Rabbits should be vaccinated at 2½-3 months of age. Annual boosters are then recommended.

Encephalitozoon cuniculi

This disease often causes a chronic latent condition in rabbits, with active disease being characterised by neurological signs such as weakness, head tilt (“torticollis”), paralysis and even seizures. It may also cause kidney failure (the organism is shed via the urine), lens changes, and heart disease. It may also be carried by rabbits with no clinical signs! Fenbendazole has been used to treat this condition though it is often too far advanced for therapy to succeed. Sadly post-mortem examination is often the only reliable way to confirm diagnosis. Encephalitozoonosis has been described in a few cases in people but its significance is not really known. This underlines the importance of always washing your hands after handling any animal and particularly before eating or preparing food.