Full Description

To improve surveillance for Cryptosporidium oocysts in water, the USEnvironmental Protection Agency developed method 1622, which consists of filtration, concentration, immunomagnetic separation, fluorescent antibody and 4,6-diamidino-2-phenylindole (DAPI) counter-staining, and microscopic evaluation. Two filters were compared for analysis of 11 stream water samples collected throughout the United States. Replicate 10-L stream water samples (unspiked and spiked with 100-250 oocysts) were tested to evaluate matrix effects. Oocyst recoveries from the stream water samples averaged 22% (standard deviation [SD] =+/-17%) with a membrane disk and 12% (SD=+/-19%) with a capsule filter. These results demonstrate that Cryptosporidium oocysts can be recovered from stream waters using method 1622, but recoveries are lower than those from reagent-grade water. This research also evaluated concentrations of indicator bacteria in the stream water samples. Because few samples were oocyst-positive, relationships between detections of oocysts and concentrations of indicator organisms could not be determined. Includes 28 references, tables.

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Edition: Vol. 93 - No. 1 Published: 01/01/2001 Number of Pages: 10File Size: 1 file , 160 KB