Two serious viral disease which can affect rabbits are myxomatosis and viral hemorrhagic disease (VHD). Both are usually fatal. Myxomatosis is the most well-known rabbit disease. It is horrible in its affliction and deadly in its action. Myxomatosis is caused by the myxoma virus of the genus Leporipoxvirus. The virus was originally intentionally introduced into Australia and Europe in an effort to control wild rabbit population. Several strains of myxoma virus exist. It is believed to be transmitted by the common rabbit flea, mosquitoes or other flying insects, but can also be transmitted by mechanical contact with food, bedding and thorns. In the United States, the virus is primarily seen in California and is extremely dangerous.
The rabbit develops swellings around the eyes, base of the ears and genitals, and blepharo-conjunctivitis which progresses to blindness. Initially, the rabbit may maintain its appetite, but will soon loose it as the disease progresses. Secondary Pasteurella pneumonia is very common and the usual cause of death. In chronic (nodular) forms of myxomatosis, the rabbit develops tumor-like swellings, especially on the ears, nose and paws, 10-15 days after infection. These will
spontaneously disappear, although the resultant scabs take long to go away.
Immunization is possible if there is an outbreak in the locality of the rabbitry, but it is not a guarantee to keep the disease
at bay. Precautions should always be taken against the entry of flying insects into the rabbitry. Fine mesh netting can be used to cover all the doors and windows. Fly sprays should not be used, as they can prove toxic to small animals. Fly repellents giving off a vapor to kill insects should only be used in a large area where there is an abundant supply of fresh air. Old-fashioned fly paper is still the best method of controlling insects within a rabbitry. Quarantine new rabbits; do not house wild rabbits with domestic ones.
Viral Hemorrhagic Disease, also known as VHD, RHD, RCV, or RCD, is a highly contagious disease caused by a calicivirus which affects only domestic rabbits and the European wild rabbits from which they are descended. It can spread through any object that has come in contact with an infected rabbit. It frequently causes sudden death with no prior signs of illness. The disease progresses in 1-3 days after infection and mortality rates approach 90%. It typically affects rabbits over 2 months of age. Bleeding from the nose, mouth, or rectum is sometimes seen. Other clicnical signs include fever, lethargy, loss of appetite, difficulty breathing, rapid flips, turns, and shrill cries. Survivors become carriers of the disease and shed virus for 4 weeks, spreading it to other rabbits. There is no treatment or cure for this disease.