Tokyo Food Safety Information Center » Good things to know »  The microorganisms which cause food poisoning » Cyclospora



Cyclospora is a protozoan parasite and exists in the natural environment in the form of oocyst (dormant form) like cryptosporidium.

Although its resistance against chlorine, chemicals, and temperatures is unknown, it is thought that disinfection is difficult through the concentrations of chlorine used in drinking water, etc.

Sources of infection:

In general, infections are thought to occur via ingesting of contaminated drinking water in outbreak areas.  Infections occur by ingestion of water and foods contaminated by matured oocysts in the outer environment.  As the oocysts discharged from the human body through feces are immature, infections never occur directly from recently discharged feces.


The incubation period is thought to be approximately one week.  The main symptom is diarrhea, often accompanied by abdominal discomfort, slight fever, and weight loss.

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