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NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

CSTE Position Statement(s)

  • 10-ID-15

Clinical Description

A gastrointestinal illness characterized by diarrhea, abdominal cramping, fever, nausea, vomiting and/or anorexia.

Laboratory Criteria For Diagnosis

Probable: The detection of Cryptosporidium antigen by immunodiagnostic methods.*

Confirmed: The detection of Cryptosporidium organisms or DNA in stool, intestinal fluid, tissue samples, biopsy specimens, or other biological sample.**

* Test results known to be obtained with commercially-available immunochromatographic card tests are limited to meeting "probable" case criteria due to a recent report of unacceptably high rates of false-positive results.1

** The confirmed laboratory criteria include detection of Cryptosporidium by established laboratory methods (e.g., direct fluorescent antibody [DFA] test or polymerase chain reaction [PCR]).

Case Classification


A case that meets the clinical description and has probable criteria for laboratory diagnosis or that is epidemiologically linked to a confirmed case.


A case that meets the clinical description and the respective criteria for laboratory-confirmation as described above.


  1. Clin Infect Dis. 2010 Apr 15;50(8):e53-55).

Related Case Definition(s)