Sarcocystis (Sarco)

General description

  • Sarco is caused by a protozoan organism called Sarcocystis.
  • Sheep are the intermediate hosts and cats are the final hosts.


  • Sheep are infected by eating sporocysts in cat faeces.
  • The parasite is common in cooler climates.

Clinical signs

  • Sheep will show no clinical signs.


  • Cysts cannot be detected in live animals but are readily seen by examining the animal at the abattoir.
  • Sarcocystis cysts are white and resemble grains of rice.
  • They occur inthe oesophagus, tongue, diaphragm and skeletal muscle.


  • There is no treatment for the cysts in sheep.


  • Keep livestock feed secure from access by cats.
  • Restrict domestic cats (and dogs) from access to offal and uncooked sheep meat.
  • Dispose of carcasses immediately so they cannot be accessed by predators, including cats.
  • Control feral cat populations.

Learn more

Fact Sheet - Sarcocystis