ISSN 2398-2950      



Vetstream Ltd

Diane Addie

Synonym(s): E. cuniculi, Nosema cuniculi


  • CauseEncephalitozoon cuniculi is thought to be a significant cause of neurological signs and renal failure in pet, meat, and laboratory rabbits (Oryctolagus cuniculus),  and an important cause of cataracts and lens-induced uveitis in the rabbit. The incidence in pet rabbits is so far unknown.
  • E. cuniculi is also a cause of uveitis and cataract in cats.
  • It is not known if infection with E. cuniculi alone is sufficient to cause disease, however it is undoubtedly able to cause disease in immunocompromised individuals.
  • Signs: uveitis, cataract, neurological problems, urinary incontinence.
  • Diagnosis: PCR, ELISA, serum protein electrophoresis, biopsy, histopathology and immunohistochemistry for spore detection.
  • Treatment: fenbendazole.
  • Prognosis: moderate for cats provided they can be treated; poor for neurologically affected rabbits.



  • E. cuniculi (previously known as Nosema cuniculi) is an obligate intracellular microsporidian parasite.


  • Central nervous system lesions produce signs related to focal non-suppurative granulomatous meningoencephalomyelitis and perivascular lymphocytic infiltration.
  • Ocular lesions appear to arise from protozoan spores deposited in the developing lens after vertical transmission in utero which, during the rabbit's life, erupt within and from the lens giving cataract and/or lens-induced uveitis from lens rupture.
  • Transmission is by oral consumption of urine infected with spores from the renal lesions caused by the organism in rabbits. Carnivores are infected by consumption of milk containing spores, and infected meat from rabbits, goats, horses, pigs, wild birds, etc.
  • Anecdotal reports of associated renal failure in rabbits have been made.
  • Inhalation of spores and transplacental infection is also thought to be possible.


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Further Reading


Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Addie D D, Tasker S, Boucraut-Baralon C, Belák S, Egberink H, Frymus T, Hartmann K, Hofmann-Lehmann R, Marsilio F,  Lloret A, Lutz H, M G, Thiry E, Truyen U, Hosie M J, Möstl K (2020) Encephalitozoon cuniculi infection in cats: European guidelines from the ABCD on prevention and managementJ Feline Med Surg 22(11), 1084-1088 PubMed.
  • Sak B, Vecková T, Brdíčková K, Smetana P, Hlásková L, Kicia M, Holubová N, McEvoy J, Kváč M (2019) Experimental Encephalitozoon cuniculi Infection Acquired from Fermented Meat Products. Foodborne Pathog Dis 16(6), 394-398 PubMed.
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