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A genus belonging to the family Sarcocystidae, and includes one species, Toxoplasma gondii, the causative agent of toxoplasmosis


Toxoplasma is a genus of the taxonomic family Sarcocystidae. There is only one species in this genus, i.e. Toxoplasma gondii. It is also medically important as it is the causative agent of toxoplasmosis. The species is an obligate intracellular protozoon. The species is capable of infecting various warm-blooded animals but domestic cats are its definitive hosts. Its infective stage is the oocysts containing the pathogen in the faeces of cats (the definitive host), usually by contaminated soil, direct exposure to infected faeces, tissue cysts in infected meat or tachyzoites (proliferating forms) in blood.

Toxoplasma gondii was found in Ctenodactylus gondi (gundi) and named by Nicolle and Manceaux in 1908. Subsequent discoveries of similar organisms were later on regarded as only a single species based on the similarity of structure and nonspecificity for hosts.1

Word origin: Ancient Greek tóxon (“bow”) + plásma (“something molded, bow-shaped form")

Scientific classification:

  • Domain: Eukaryota
  • Phylum: Apicomplexa
  • Class: Conoidasida
  • Order: Eucoccidiorida
  • Family: Sarcocystidae
  • Subfamily: Toxoplasmatinae
  • Genus: Toxoplasma [Nicolle & Manceaux, 1909]

See also:

1 Olsen, O. (1986). Animal parasites: their life cycles and ecology. New York: Dover. p.168.