Compositions and methods for detecting the presence of cryptosporidium organisms in a test sample

A probe comprising a detectable label and a target binding region that fully hybridizes to a target sequence present in target nucleic acid derived from Cryptosporidium organisms in a test sample under stringent conditions to form a probe:target hybrid stable for detection, the target sequence being selected from the group consisting of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3 and SEQ ID NO:4, wherein the probe does not comprise a base region in addition to the target binding region that is capable of stably binding to the target nucleic acid under the stringent conditions, and wherein the probe does not hybridize to nucleic acid derived from a non-Cryptosporidium organism in the test sample to form a probe:non-target hybrid stable for detection under the conditions.