ISSN 2398-2969      

Sarcocystis cuniculi


Synonym(s): S. cuniculi




  • Kingdom: Protista.
  • Phylum: Apicomplexa.
  • Class: Conoidasida.
  • Order:  Eucoccidiorida.
  • Family: Sarcocystidae.
  • Genus:Sarcocystis.
  • Species:cuniculi.


  • From the Greek sarko (flesh/muscle) and kustis (bladder/pouch/bag/cyst).

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Clinical Effects



  • Members of the genusSarcocystisare obligate intracellular protozoal parasites.


  • Members of the genusSarcocystisare intracellular protozoal parasites with a typical coccidian lifecycle. As such they demonstrate merogony, gamogony and sporogony.
  • Sarcocystisspp have an indirect lifecycle, and must develop in both an intermediate and a definitive host.
  • The definitive host becomes infected when it ingests encysted parasites (sarcocysts) in muscle tissues.
  • Sarcocysts are filled with hundreds or even thousands of bradyzoites. The bradyzoites are released in the intestine of the definitive host, where they enter the lamina propria and immediately undergo gamogony to form oocysts.
  • The oocysts mature in the hosts cells and are then shed in the feces. These oocysts contain two sporocysts, each with four sporozoites.
  • The oocysts may disintegrate allowing sporocysts to be passed in the feces.
  • The intermediate host becomes infected following the ingestion of oocysts or sporocysts in contaminated food or water.
  • In domestic animals, such as the rabbit, acting as intermediate hosts forSarcocystisspp, the asexual development of the parasite consists of one to three generations of endopolygeny in endothelial cells of capillaries or arterioles.
  • Endozoites from this last generation of endopolygeny initiate the formation of cysts in various striated muscles, and sometimes also in cells of the CNS or Purkinje fibers of the heart.
  • Mature cysts contain several hundred thousand cystozoites, which do not divide further and are the terminal asexual stage in the intermediate host.


  • The transmission ofSarcocystis cuniculifrom rabbits to cats following the ingestion of infected rabbit meat has been confirmed experimentally.
  • One study demonstrated the transmission ofSarcocystis cuniculito rabbits following ingestion of sporocysts passed by a cat that had, itself, been experimentally fed an infected rabbit.
  • Transmission generally occurs following ingestion of contaminated food or water.
  • The involvement of fleas has been suggested without being proven.

Pathological effects

  • In intermediate hosts, pathogenicSarcocystisspp can cause acute disease during the early phase of infection and chronic disease during the late phase of infection.
  • Little is known about the mechanisms underlying pathogenicity.
  • The severity of clinical signs is thought to depend on the dose of ingested sporocysts and the immune status of the host.
  • There are no clinical signs that are specific for sarcocystosis.
  • Heavily affected animals may demonstrate lameness.
  • One report asserts that sarcocysts can destroy muscle fibers and cause pressure atrophy of adjacent cells.


Control via animal

  • None required as current methods of meat production should ensure that food and water is not contaminated with feces, and therefore sporocysts.

Control via environment

  • Grazing should be protected to ensure that definitive hosts such as the cat do not have the opportunity to defecate in the environment and contaminate food and water supplies.
  • Where cat feces are a problem, they should be collected regularly.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource
  • Tenter A M (1995) Current research on Sarcocystis species of domestic animals. Int J Parasitol 25 (11), 1311-1330 PubMed.
  • McKenna P B & Charleston W A (1992) The survival of Sarcocystis gigantea sporocysts following exposure to various chemical and physical agents. Vet Parasitol 45 (1-2), 1-16 PubMed.
  • Elwasila M, Entzeroth R, Chobotar B et al (1984) Comparison of the structure of Sarcocystis cuniculi of the European rabbit (Oryctolagus cuniculus) and Sarcocystis leporum of the cottontail rabbit (Sylvilagus floridanus) by light and electron microscopy. Acta Vet Hung 32 (1-2), 71-78 PubMed.
  • Cerná Z, Loucková M, Nedvĕdová H et al (1981) Spontaneous and experimental infection of domestic rabbits by Sarcocystis cuniculi Brumpt, 1913. Folia Parisitol Praha 28 (4), 313-318 PubMed.
  • McKenna P B & Charleston W A (1980) Coccidia (Protozoa:Sporozoasida) of cats and dogs. I. Identity and prevalence in cats. New Zealand Vet J 28 (5), 86-88 PubMed.
  • Crum J M & Prestwood A K (1977) Transmission of Sarcocystis leporum from a cottontail rabbit to domestic cats. J Wild Dis 13 (2), 174-175 PubMed.
  • Tadros W & Laarman J J (1977) The cat Felis catus as a final host of Sarcocystis cuniculi Brumpt 1913 of the rabbit (Oryctolagus cuniculus). Proc K Ned Akad Wet (Biol Med) 80 (4), 351-352 VetMedResource.
  • Griffiths H J (1971) Some common parasites of small laboratory animals. Lab Anim (1), 123-135 PubMed.
  • Erickson A B (1946) Incidence and transmission of Sarcocystis in Cottontails. J Wild Management 10 (1), 44-46 JSTOR.
  • Manz W (1867) Beitrag sur kenntnis der miescherschen schläuche. Arch F Mikr Anat 3, 345-356.

Other sources of information

  • Pakes S P & Gerrity L W (1994) Protozoal diseases. In:The Biology of the Laboratory Rabbit. 2nd edn. Eds: Manning P J, Ringler D H & Newcome C E. Academic Press, London.
  • Dubey J P, Speer C A & Fayer R (1989) Sarcocystosis of Animals and Man. Boca Raton, California: CRC Press.
  • Brumpt E (1913) Précis de Parasitologie. Paris: Masson et cie.

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