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To assess the source and public health significance of Cryptosporidium oocyst contamination instorm water, a PCR-RFLP technique based on the small subunit rRNA gene was used in theanalysis of 40 storm water samples collected from the Malcolm Brook, New York over a oneyear period. The distribution of Cryptosporidium spp. and genotypes in storm water samplescollected in this study was compared with the data obtained from 29 storm water samples fromthe Ashokan Brook in a previous study. Most storm water samples (59 of 69) from bothwatersheds were positive for Cryptosporidium oocysts by PCR, almost all of which belonged tospecies and genotypes that have not been previously detected in humans or domestic animals.Of the 59 PCR positive samples analyzed from both watersheds, 54 (91.5%) were linked toeither known or unknown animal sources. In addition, C. hominis (W14 genotype) was detectedin several samples collected from the Malcolm Brook over a two-week period. SeveralCryptosporidium spp. were commonly found in both watersheds, including W4 (cervid)genotype from deer, W7 (muskrat) genotype from muskrats, W11 (snake) genotype from1snakes, and W1 genotype from an unknown animal source (possibly rodents). SeveralCryptosporidium spp. commonly seen in the Ashokan Brook, such as W10 genotype (C. baileyi)from birds, W2 (opossum genotype I) and W8 (opossum genotype II) from opossums, and W6from unknown animals, were not detected in samples from Malcolm Brook. Likewise, severalwildlife genotypes commonly seen in Malcolm Brook were not seen in samples from AshokanBrook, such as W15 (animal source unknown), W16 (possibly a fox parasite), and W17(possibly a rodent parasite). Altogether, 18 Cryptosporidium parasites were found in stormwater samples from these watersheds, only 12 of which could be attributed to knownspecies/groups of animals. Aliquots of 37 samples from the Malcolm Brook were also analyzedby EPA Method 1623; 16 of the samples were positive by microscopy, with 1-4 oocysts peraliquot. In contrast, all microscopy-positive and 13 of the 21 microscopy-negative sampleswere positive by PCR. Results of the study indicate that molecular techniques can complementtraditional detection methods by providing information on the source of contamination andhuman-infective potential of Cryptosporidium oocysts found in water. Includes 32 references, tables, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 15File Size: 1 file , 700 KB