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EVALUATION OF AN ALTERNATIVE IMS DISSOCIATION PROCEDURE FOR USE WITH METHOD 1622: DETECTION OF CRYPTOSPORIDIUM IN WATER
Citation:
Ware, M W., L Wymer, H.D 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).
Impact/Purpose:
1) Refine new, practical methods for the detection of CCL-related and emerging waterborne human protozoa.
2) Perform field tests of devices or methods that have been developed under this task.
3) Evaluate these methods or devices in a variety of water matrices and parasite concentrations.
This work in this task supports CCL2 and 3 and is expected to be completed by 9/07.
Description:
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.