Encephalitozoon cuniculi is a one-celled, obligate intracellular organism called a microsporidium. Rabbits 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. Three strains are recognized: Strain I (affects rabbits, mice, and humans), Strain II: (blue foxes, mice, and cats), and Strain III (domestic dogs and humans). There are several unclassified strains that affect guinea pigs, hamsters, cows, mink, nonhuman primates, birds, and reptiles. There is a zoonotic potential to those with HIV/AIDS and other immunosuppressive disorders.
Rabbits may be asymptomatic carriers or develop neurologic, kidney, or eye disease. Neurologic disease is characterized by a head tilt, rolling, unsteady gait, paralysis, and urinary incontinence. Kidney disease results in a condition called chronic Interstitial Nephritis resulting in weight loss, increased urination, increased thirst, and bladder inflammation. Eye or ophthalmic disease presents with cataracts and a condition called phacoclastic uveitis where the cataract-affected lens appears to almost liquify.
Conditions that appear similar include middle and internal ear infections, trauma, ear mites, and neurologic tumors.
Your veterinarian will recommend serological testing called an ELISA along with testing for C-reactive protein (CRP) an acute phase protein. An IgM titer of at least 1:64 means that there’s an 88% chance the rabbit is infected. If this titer is observed with an IgG titer of greater than or equal to 1:512 and/or an elevated CRP result, the chance the rabbit is truly positive is 92-100%.
Your vet may also recommend a complete blood count and serum biochemistry, radiographs, and CT imaging depending on the patient’s clinical signs.
Unfortunately, there is still a lot we do not know about this organism and few studies have been published in regards to the efficiency of treatments. Currently, treatment involves Fenbendazole and supportive care with pain management, assist feeding, subcutaneous fluids, physical therapy, and anti-nausea medications.
The prognosis is dependent on which systems are affected and to what degree. If present, head tilt may be permanent even if treated due to permanent damage.
Recheck is recommended in 7-14 days or sooner if not doing better. Additional rechecks may be recommended depending on the response to therapy.
Copyright © All Rights Reserved
