Lapis ISSN 2398-2969


Synonym(s): E. cuniculi, Nosema cuniculi

Contributor(s): David L Williams, Emma Keeble, Molly Varga, Vetstream Ltd


  • CauseE. cuniculi  Encephalitozoon cuniculi  is thought to be a significant cause of neurological signs and renal failure in pet and laboratory rabbits and an important cause of cataracts and lens-induced uveitis in the rabbit. The incidence in pet rabbits is so far unknown.
  • It is not known if infection with E. cuniculiinfection alone is sufficient to cause disease.
  • Signs: neurological problems, urinary incontinence.
  • Diagnosis: ELISA, serum protein electrophoresis, biopsy, histopathology.
  • Treatment: albendazole/fenbendazole.
  • Prognosis: poor for neurologically affected animals.

Print off the owner factsheets onEncephalitozoon cuniculi  Encephalitozoon cuniculi  and Samples - how they help your vet  Samples - how they help your vet  to give to your clients.




  • Unknown in the UK in pet rabbits, though thought to be relatively common.


  • Urinary incontinence   Urinary incontinence   precedes neurological signs.
  • Neurological signs are often terminal   Head tilt: otitis media  .


  • Young rabbits more often affected.


  • Dwarf breeds   Dwarf Lop    Netherland Dwarf  have overt clinical signs such as head tilt   Encephalitozoonosis paralysis  more commonly than standard breeds.


  • Commonly fatal.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Varga M (2014) Questions around Encephalitozoon cuniculi in rabbits. Vet Rec 174 (14), 347-348 PubMed.
  • Hein J, Flock U, Sauter-Louis C et al (2014) Encephalitozoon cuniculi in rabbits in Germany: prevalence and sensitivity of antibody testing. Vet Rec 174 (14), 350 PubMed.
  • Richardson V (2012) Urogenital diseases in rabbits. In Pract 34 (10), 554-563 VetMedResource.
  • Wright I (2011) Encephalitozoon cuniculi: Infecting the rabbit next door. UK Vet: Companion Animal 16, 49-50 VetMedResource
  • Keeble E (2011) Companion animal practice: Encephalitozoonosis in rabbits - what we do and don't know. In Pract 33 (9), 428-435 VetMedResource.
  • Jass A, Matiasek K, Henke J et al (2008) Analysis of cerebrospinal fluid in healthy rabbits and rabbits with clinically suspected encephalitozoonosis. Vet Rec 162 (19), 618-622 PubMed.
  • Keeble E (2006) Common neurological and musculoskeletal problems in rabbits. In Pract 28 (4), 212-218 VetMedResource.
  • Harcourt-Brown F M & Holloway H K (2003) Encephalitozoon cuniculi in pet rabbits. Vet Rec 152 (14), 427-431 PubMed.
  • Suter C, Müller-Doblies U U, Hatt J M et al (2001) Prevention and treatment of Encephalitozoon cuniculi infection in rabbits with fenbendazole. Vet Rec 148 (15), 478-480 PubMed.
  • Boot R, Hansen A K, Hansen C K et al (2000) Comparison of assays for antibodies to Encephalitozoon cuniculi in rabbits. Lab Anim 34 (3), 281-289 PubMed.
  • Feaga W P (1997) Wry neck in rabbits. JAVMA 210 (4), 480 PubMed.
  • Levkut M, Horváth M, Bálent P et al (1997) Catecholamines and encephalitozoonosis in rabbits. Vet Parasitol 73 (1-2), 173-176 PubMed.
  • Stiles J, Didier E, Ritchie B et al (1997) Encephalitozoon cuniculi in the lens of a rabbit with phacoclastic uveitis - confirmation and treatment. Vet Comp Ophthalmol (4), 233-238 VetMedResource.
  • Thomas C, Finn M, Twigg L et al (1997) Microsporidia (Encephalitozoon cuniculi) in wild rabbits in Australia. Austr Vet J 75 (11), 808-810 PubMed.
  • Nast R, Middleton D M & Wheler C L (1996) Generalized encephalitozoonosis in a Jersey wooly rabbit. Can Vet J 37 (5), 303-305 PubMed.
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  • Wesonga H O & Munda M (1992) Rabbit encephalitozoonosis in Kenya. Lab Anim 26 (3), 219-221 PubMed.
  • Greenstein G, Drozdowicz C K, Garcia F G et al (1991) The incidence of Encephalitozoon cuniculi in a commercial barrier-maintained rabbit breeding colony. Lab Anim 25 (4), 287-290 PubMed.
  • Kunstyr I & Naumann S (1985) Head tilt in rabbits caused by pasteurellosis and encephalitozoonosis. Lab Anim 19 (3), 208-213 PubMed.
  • Cox J C & Ross J (1980) A serological survey of Encephalitozoon cuniculi infection in the wild rabbit in England and Scotland. Res Vet Sci 28 (3), 396 PubMed.
  • Gannon J (1980) A survey of Encephalitozoon cuniculi in laboratory animal colonies in the United Kingdom. Lab Anim 14 (2), 91-94 PubMed.
  • Cox J C, Hamilton R C & Attwood H D (1979) An investigation of the route and progression of Encephalitozoon cuniculi infection in adult rabbits. J Protozool 26 (2), 260-265 PubMed.
  • Flatt R E & Jackson S J (1970) Renal nosematosis in young rabbits. Pathol Vet (6), 492-497 PubMed.