Abstract: A method for selectively detecting the presence of C. parvum organisms in a sample. A method for selectively detecting the presence of C. parvum organisms and for detecting the presence of G. lamblia organisms, simultaneously, in a sample. A method for selectively detecting viable C. parvum organisms in a sample potentially containing viable C. parvum organisms. A method for selectively detecting viable C. parvum organisms and for detecting viable G. lamblia organisms, simultaneously. A method for selectively detecting infectious C. parvum organisms in a sample, and in another embodiment, additionally comprising detecting viable G. lamblia organisms in the sample, simultaneously. Kit for use in performing these methods.

Abstract: The subject invention provides processes and kits for detecting encysted forms of protozoa, particularly Cryptosporidium and Giardia, that are viable and infectious. To determine viability, cysts or oocysts are heated to a temperature that induces transcription of heat shock protein (HSP) genes. Alternatively, to determine infectivity the encysted forms are inoculated onto susceptible cell cultures. The viability or infectivity of the encysted forms can be determined by synthesizing a cDNA from an induced HSP RNA template using a primer that is specific for particular genus or species of protozoa, followed by enzymatic amplification of the cDNA. Alternatively, infectivity can be determined by amplifying HSP DNA from infected cells using a primer pair that is specific for a particular genus or species of protozoa. Amplified HSP DNA can be detected using probes that are specific for a protozoan species of interest, such as the human pathogens C. parvum and G. lamblia.