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Evaluation of An Alternative Ims Dissociation Procedure for Use With Method 1622: Detection of Cryptosporidium in Water
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| Abstract: | U.S. EPA Method 1623 is used to detect and quantify Cruptosporidum spp. oocysts in ater. The protocol consists of filtration, immunomagnetic separation (IMS), staining with a fluorescent antibody, and microscopic analysis. Microscopic analysis includes detection by fluorescent antibody and confirmation by the demonstration of 1-4 sporozoites or nuclei after staining with 4',6-diamidino-2-phenyl indole dihydrochloride (DAPI). Confirmation is required because some algae appear to be oocysts when using this fluorescent antibody method. The purpose fo this study was to develop and evaluate a new IMS dissociation using a 10 minute incubation at 80 degrees C. Using this adaptation, the average oocyst recovery rate improved from 41% to 71% in seeded reagent water samples, and from 10% to 51% in seeded river samples. The average oocyst confirmation rate by DAPI improved from 49% to 93% in reagent water samples and from 48% to 73% in river water samples. This modification improved Method 1623 by increasing both the oocyst recovery and DAPI confirmation rates.
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| Citation: | Ware, M. W., L. Wymer, H. A. Lindquist, and F. W. Schaefer III. Evaluation of An Alternative Ims Dissociation Procedure for Use With Method 1622: Detection of Cryptosporidium in Water. WATER RESEARCH. Elsevier Science Ltd, New York, NY, 55(3):575-583, (2003). |
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| Contact: |
Mary P. O'Bryant - (919)-541-4871 or obriant.mary@epa.gov
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| Division: |
Microbiological & Chemical Exposure Assessment Division |
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| Branch: |
Biohazard Assessment Research Branch |
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| Product Type: |
Journal |
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| Published: |
12/01/2003 |
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