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IDENTIFICATION OF CRYPTOSPORIDIUM SPECIES AND THE SOURCES IN RAW WASTEWATER USING A SMALL SUBUNIT RRNA-BASED PCR-RFLP TOOL
Citation:
Xiao, L., S. Glaberman, J. Limor, A. Lal, A. Singh, S. Gradus, AND M D. Royer*. IDENTIFICATION OF CRYPTOSPORIDIUM SPECIES AND THE SOURCES IN RAW WASTEWATER USING A SMALL SUBUNIT RRNA-BASED PCR-RFLP TOOL. Presented at American Waterworks Association's, Water Quality Technology Conference, Nashville, TN, 11/1/2001.
Description:
The species composition and source of Cryptosporidium oocysts in wastewater have never been determined, even though it is widely assumed that these oocysts are from human sewage. Recent molecular characterizations of Cryptosporidium parasites make it possible to differentiate human pathogenic Cryptosporidium parasites from those that do not infect humans, and to track the source of Cryptosporidium oocyst contamination in the environment. In this study, a small subunit (SSU) rRNA based PCR-RFLP technique was used for the detection and characterization of Cryptosporidium oocysts in wastewater. Eight to 15 daily 24-hr composite samples were collected each month from a wastewater treatment plant in Milwaukee, WI. Each sample contained 10 or 50 ml of raw wastewater, and was processed by immunomagnetic separation, DNA extraction and PCR-RFLP analysis. To date, 177 samples have been analyzed and 46 of them were PCR positive for Cryptosporidium parasites. Seven Cryptosporidium prasites were found. Eight samples had oocysts of mixed Cryptosporidium paraistes. No significant monthly differences were seen in the overall sample positivity and positivity for each Cryptosporidium species and genetype. The data indicate that not only humans, but also cattle slaughterhouses, rodents, and urban wildlife all contribute to Cryptosporidium contamination of the raw wastewater. The frequent occurrence of C. andersoni, C. muris, and the Cryptosporidium deer genotype suggests that nonhuman pathogenic Cryptosporidium parasites are a major component of Cryptosporodium oocysts in this wastewater.