Identification of species and sources of Cryptosporidium oocysts in storm waters with a small-subunit rRNA-based diagnostic and genotyping tool

The identification of Cryptosporidium oocysts in environmental samples is l argely made by the use of an immunofluorescent assay. In this study, we hav e used a small-subunit rRNA-based PCR-restriction fragment length polymorph ism technique to identify species and sources of Cryptosporidium oocysts pr esent in 29 storm water samples collected from a stream in New York. A tota l of 12 genotypes were found in 27 positive samples; for 4 the species and probable origins were identified by sequence analysis, whereas the rest rep resent new genotypes from wildlife. Thus, this technique provides an altern ative method for the detection and differentiation of Cryptosporidium paras ites in environmental samples.