Encephalitozoonosis (E. cuniculi)
Encephalitozoon cuniculi (ECUN) is a microsporidian parasite related to fungi. Rabbits can become infected while developing in their mother’s uterus, or by ingesting or inhaling spores passed in the urine or feces of an already-infected rabbit. Ingested spores pass through the intestinal wall into the bloodstream, where they travel to other areas of the body — most commonly the kidneys, eyes, and brain.
Most rabbits show no signs of disease early in the infection. In some individuals, the disease progresses and can have serious consequences, including death, if the immune system fails to contain it.
Infection in the brain can result 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.
Diagnosis
An antibody test is performed in ELISA format on a small blood sample. Results are 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 measured as part of the test using a standardized automated assay that provides quantitative results.
Treatment
There is no known cure for E. cuniculi. However, treatment with an anti-parasitic medication called Fenbendazole will very often control the parasite and manage symptoms. Additional supportive treatments may include assisted feedings, hydration, anti-inflammatories, anti-dizziness medication, and eye treatments when head tilt is present. Some rabbits may have a permanent head tilt following recovery.
