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Cryptosporidiosis (Cryptosporidium spp.)
2012 Case Definition

CSTE Position Statement(s)

  • 11-ID-14

Clinical Description

A gastrointestinal illness characterized by diarrhea and one or more of the following: diarrhea duration of 72 hours or more, abdominal cramping, vomiting, or anorexia.

Laboratory Criteria for Diagnosis

Confirmed: Evidence of Cryptosporidium organisms or DNA in stool, intestinal fluid, tissue samples, biopsy specimens, or other biological sample by certain laboratory methods with a high positive predictive value (PPV), e.g.,

  • Direct fluorescent antibody [DFA] test,
  • Polymerase chain reaction [PCR],
  • Enzyme immunoassay [EIA], OR
  • Light microscopy of stained specimen.
Probable: The detection of Cryptosporidium antigen by a screening test method, such as immunochromatographic card/rapid card test; or a laboratory test of unknown method.

Case Classification


  • A case with supportive laboratory test results for Cryptosporidia spp. infection using a method listed in the probable laboratory criteria. When the diagnostic test method on a laboratory test result for cryptosporidiosis cannot be determined, the case can only be classified as probable, OR
  • A case that meets the clinical criteria and is epidemiologically linked to a confirmed case.


A case that is diagnosed with Cryptosporidium spp. infection based on laboratory testing using a method listed in the confirmed criteria.


Persons who have a diarrheal illness and are epidemiologically linked to a probable case because that individual was only diagnosed with cryptosporidiosis by an immunocard/rapid test/ or unknown test method cannot be classified as probable cases. These epi-links can be considered suspect cases only.