Cryptosporidia are small apicomplexan protozoan parasites that infect the intestinal tract of humans and animals. Infected humans and animals shed small (4-6 micrometer in diameter) infectious oocysts in their stool, and these can subsequently contaminate and survive in recreational and drinking water supplies. use of this test or the multiplex gastrointestinal polymerase chain reaction (PCR) panel (GIP / Gastrointestinal Pathogen Panel, PCR, Feces) is recommended for sensitive and specific detection. This antigen test is ideal for situations in which cryptosporidiosis is highly suspected (eg outbreak scenarios), whereas the PCR panel allows for simultaneous detection of multiple parasitic, viral, and bacterial causes of diarrhea. When symptoms are present, they usually include profuse watery diarrhea, malaise, anorexia, nausea, crampy abdominal pain, and low-grade fever. When symptoms are present, they usually include profuse watery diarrhea, malaise, anorexia, nausea, crampy abdominal pain, and low-grade fever.