What is Rabbitpox?
A rare disease, rabbitpox has been seen in laboratory rabbits who have been infected by a virulent strain of the vaccinia virus or a virus that is closely related. Rabbitpox is a poxvirus (f. Poxviridae) and in the United States, a few outbreaks of this viral disease have been reported since 1930 when it was first diagnosed. Rabbitpox has also been seen in the Netherlands. Skin symptoms in the form of pox lesions may develop on the rabbit, and many also experience fever and nasal discharge (around two or three days after infection). The disease is very contagious and has a high rate of mortality. Though the disease is seen in laboratory rabbits, rabbitpox is not recognized in wild rabbits.
An acute generalized disease seen in laboratory rabbits, rabbitpox is caused by a virus closely related to vaccinia virus and includes skins lesions, fever and nasal discharge.
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Symptoms of Rabbitpox in Rabbits
Rabbits that have rabbitpox will often develop skin lesions (around five days after first becoming infected) that are accompanied with fever, nasal discharge, facial swelling, lack of interest in eating and a lack of energy. Some rabbits may have pink or yellow lesions on their cornea and lesions elsewhere on their body may be obvious or only noticed when the rabbit is carefully examined. A rabbit may develop multiple pox lesions though that is not always the case; lesions may be in one place or throughout the rabbit’s body. Usually there is a progression of papules to vesicles (smalls structures in the cell), which leads to crusting ulcers upon the abrupt separation of the vesicles. The significant swelling that a rabbit experiences as a result of rabbitpox will lead to his having enlarged lymph nodes.
- Nasal discharge
- Enlarged lymph nodes
For rabbits that don’t survive the infection with rabbitpox, death will occur on average between seven to ten days after infection. Some rabbits lose their battle at around five days after infection and others several weeks after they have become infected.
Rabbitpox can present with lesions or without lesions. Should there be no lesions present, the disease may be called pockless rabbitpox. Pockless rabbitpox occurred in a sudden outbreak in laboratory rabbits in Holland in 1941. Just like with rabbitpox, rabbits that developed pockless rabbitpox had a high mortality rate.
Causes of Rabbitpox in Rabbits
Rabbitpox is a poxvirus (f. Poxviridae) caused by a virus that is closely related to the vaccinia virus. Found in laboratory rabbits, the disease is known to be spread among rabbits through their grooming of one another as well as through their nasal discharge. The disease can also be spread by biting insects like mosquitoes. Rabbitpox has only been recorded in the United States and in the Netherlands and has only been seen in laboratory rabbits.
Diagnosis of Rabbitpox in Rabbits
A veterinarian will diagnose a rabbit with rabbitpox based on the symptoms he is exhibiting as well as through a histological examination. PCR assays may be available though they are not often obtained for clinical use. Shope fibromas and myxomatosis are other diseases that cause pox-like lesions, and these will have to be eliminated as possible diagnoses by the veterinarian prior to a diagnosis of rabbitpox being given.
Treatment of Rabbitpox in Rabbits
No treatment is typically provided for rabbits that are experiencing rabbitpox. Topical antimicrobial and anti-inflammatory ointments have been proven to be helpful for the rabbit in his recovery from the infection. Though it has been found to sometimes be poisonous to kidneys, cidofovir, an antiviral medication, has proven to be effective against poxviruses in rabbits, making it a possible treatment option. NSAID’s, fluid therapy and assisted feeding are other options to help rabbits overcome the infection and feel more comfortable. Younger rabbits, and those that are pregnant or lactating, are the most likely rabbits to succumb to a rabbitpox infection.
Recovery of Rabbitpox in Rabbits
Rabbits infected with rabbitpox will benefit from supportive care. While no treatment is typically given, there are things that can be done to help the rabbit be more comfortable while he fights the infection. Should the rabbit need to be anesthetized while recovering, if his respiratory tract has been impacted by rabbitpox, the veterinarian will want to take special care. It is important to note that should a rabbit develop rabbitpox, once he has recovered he will not be a carrier of the infection.
The smallpox vaccine will be effective in rabbits for developing immunity to rabbitpox, making this an option that will eliminate the concern of rabbits contracting rabbitpox. Fortunately rabbitpox does not infect people so handling the rabbits during their infection with rabbitpox will not cause illness.