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Floppy Rabbit Syndrome investigation

Background information

Tetraplegic rabbit'Floppy Rabbit Syndrome' (FRS) is an acute neurological condition that affects rabbits. It is characterised by a sudden inability to hop around. The muscles of the legs and, in some cases, the neck are flaccid. Affected rabbits are mentally normal and will eat and drink if food and water is placed close to them. They can urinate and defaecate. Many cases recover although some rabbits are euthanased because of the severity of the symptoms and lack of awareness by the owner or veterinary surgeon that recovery is possible. Death from respiratory failure can occur. Some rabbits only have a single episode. Others have repeated episodes. A video of a rabbit affected by FRS can be seen here

The cause of FRS is unclear.  Little or no scientific literature exists on the clinical presentation, pathologic changes and potential underlying processes of FRS patients. Infectious causes (Encephalitozoon cuniculi, Toxoplasma gondii, Sarcocystis cuniculi, and Clostridium botulinum), metabolic causes (hypokalaemia, vitamin E/selenium deficiency), plant toxicity and myasthenia gravis have all been put forward as potential aetiologies but there is no supporting evidence for any of these ideas. Paralysis due to trauma is another possibility. At the present time, the diagnosis of FRS is entirely based on clinical suspicion, supported by neurological examination and exclusion of other causes.  Blood sampling for antibodies to Encephalitozoon cuniculi is important as this is the major differential diagnosis.  Investigations are underway (see below) to see if a specific blood test for FRS is al possibility. More expensive tests such as CT/MRI scanning, cerebrospinal fluid analysis and electromyelography can also help with making a diagnosis but are not widely available. They can show another problem (e.g. a tumour or fractured spine) that could be causing the clinical signs. 

Clinical Research Project

The clinical features of FRS has similarities with Coonhound paralysis in dogs and Guillain-Barré syndrome in people. These conditions are attributed to an autoimmune disorder manifested by a polyradiculoneuritis associated with specific antibodies to surface structures of the peripheral nerves (anti-glycolipid antibodies). Angie Rupp, a veterinary pathologist who has published on acute canine radiculoneuritis, is interested in FRS. Together, we are conducting a clinical research project to investigate the possibility that FRS is also an immune-mediated disorder of the peripheral nerves and that, if present, anti-ganglioside antibodies could be used as a diagnostic test for the disease. We are interested in any factors that might trigger episodes and the possibility of a familial predisposition. Any relationship with Encephalitozoon cuniculi  is also of interest.

The project has been granted ethical approval by the University of Glasgow, School of Veterinary Medicine, Research Ethics Committee (Ref 63a/16). All samples will be archived at the University of Glasgow. 

Appeal for information and material.

We are appealing for clinical information about cases and blood samples. We would also appreciate the opportunity to conduct a post-mortem examination on any rabbits that die from the condition. Transportation to the University of Glasgow can be arranged.

If you own a rabbit that is suffering from the condition, please fill in our online questionnaire.  There will be no immediate results from this survey but your input is valuable. Please get your vet to submit any surplus blood from other tests, such as profiles or E. cuniculi serology that are run. Blood samples are the most important part of our investigation. More information and a submission form can be downloaded. Informed consent from the owner is a pre-requisite. A client information and consent form can be downloaded for the owner to sign. If a vet wishes to discuss a case, please email