M.D. Sobsey
F. W. Schaefer III
D.S. Francy
Rebecca A. Nally
C.D. Heaney
O. D. Simmons III
2001
<p><span>To improve surveillance for </span><i>Cryptosporidium</i><span> oocysts in water, the US Environmental 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 = ±6%) with a capsule filter. Oocyst recoveries from reagent water precision and recovery samples averaged 39% (SD = ±13%) with a membrane disk and 47% (SD = ±19%) with a capsule filter. These results demonstrate that </span><i>Cryptosporidium</i><span> 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.</span><span></span></p>
application/pdf
10.1002/j.1551-8833.2001.tb09101.x
en
American Water Works Association
Evaluation of USEPA method 1622 for detection of Cryptosporidium oocysts in stream waters
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