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Claire Italiano, MBBS, FRACP, DTMH, MPHTM
David O Freedman, MD
Section Editor
Edward T Ryan, MD, DTMH
Deputy Editor
Elinor L Baron, MD, DTMH


Sarcocystosis is a zoonotic infection caused by a protozoan parasite of the genus Sarcocystis, of which there are more than 200 known species [1-4]. Depending on the infecting species and nature of the ingested material, two distinct clinical syndromes may occur in humans: intestinal sarcocystosis or muscular sarcocystosis.

Three species of Sarcocystis have been identified in human infection [5,6]. Sarcocystis hominis and Sarcocystis suihominis cause gastrointestinal disease; humans serve in the natural infection cycle [5]. Sarcocystis nesbitti, a snake species, has been recognized as a cause of human muscular sarcocystosis in Malaysia; humans are accidental, dead-end intermediate hosts [6].


Livestock universally harbor Sarcocystis infection worldwide. Symptomatic and asymptomatic gastrointestinal infection has been reported with the highest prevalence in Europe; cases have also been reported from many Asian countries, with less frequent occurrences in Australia and North and South America [5,7-11].

Of the approximately 190 cases of symptomatic human muscular sarcocystosis reported in the literature, the majority have occurred as part of outbreaks or case series originating from rural Malaysia [7,10-17]. The best description of the natural history of sarcocystosis is reflected in a report of 89 cases that occurred during a definitive point-source outbreak in early 2012 on Pangkor Island off the west coast of Malaysia [14]. Subsequently, 68 cases presenting late in the clinical evolution of disease were attributed retrospectively to exposures on Tioman Island off the east coast of Malaysia in 2011 and 2012 [15]. Other countries with reported exposure include India and Thailand [18-21]; only one symptomatic case has been described with no evident exposure in Asia [22].

Tissue sarcocysts of unknown species have been observed in asymptomatic individuals from countries including Singapore, Malaysia, Thailand, India, and Uganda; the human pathogenicity of these organisms is not known [21,23-25].

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Literature review current through: Nov 2017. | This topic last updated: Feb 24, 2017.
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