Encephalitozoonosis (E. cuniculi)

Encephalitozoon cuniculi (ECUN) is a microsporidium parasite related to fungi. Rabbits can either become infected while they develop within their mother's uterus or by either ingesting or inhaling spores passed in the urine or feces from rabbits already carrying the disease. Ingested spores pass through the walls of the intestine into the blood where they then travel to other areas of the body. In most rabbits,the disease spreads onward to the kidneys, eye and brain.  Most rabbits show no signs of disease early on in the infection. In some rabbits the disease progressing and can have serious consequences including death if their immune system fails to contain it.  Infection that takes place in the brain results in head tilt and may cause other signs such as weakness, paralysis, altered appetite, tremors or seizures. In the eye, E. cuniculi causes cataracts and sometimes a condition called phacoclastic uveitis. 


An antibody test is performed in the ELISA format on a small blood sample and results are currently reported as a titer. All samples are screened at a 1:64 dilution for IgM and IgG E. cuniculi specific antibodies. C-Reactive Protein is a standardized automated assay providing quantitative results as part of the test.


There is no known cure for E. cuniculi, however, treatment with an anti-parasitic medication called Fenbendazole will very often control the parasites and treat the symptoms.  Other treatments can include supportive feedings, hydration, anti-inflammatories, dizziness medicine, and eye treatments if there is a head tilt. Some rabbits may continue to have a permanent head tilt after recovery.