You are here:
EVALUATION OF CRYPTOSPORIDIUM OOCYST RECOVERY IN WATER BY EPA METHOD 1623 WITH A MODIFIED IMS DISSOCIATION PROCEDURE
Citation:
Ware, M W., L Wymer, H.D A. Lindquist, AND F W. Schaefer III. EVALUATION OF CRYPTOSPORIDIUM OOCYST RECOVERY IN WATER BY EPA METHOD 1623 WITH A MODIFIED IMS DISSOCIATION PROCEDURE. Presented at International Symposium on Waterborne Pathogens, Lisbon, Portugal, September 22-25, 2002.
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 Methods 1622 and 1623 are used for the detection of waterborne Cryptosporium. These methods consist of filtration, elution, purificaiton by immunomagnetic separation (IMS), and microscopic analysis for oocysts stained by a fluorescent monoclonal antibody and counter stained with 4',6-diamidino-2-phenyl indole (DAPI). DAPI counter staining is used to confirm oocysts and reduce the number of false positives. This study compared the IMS acid dissociation with heat with heat only dissociation of the parasite from the immunomagnetic beads. The effect of this change was evaluated by analyzing 48 reagent and river water samples. The average oocyst recovery in these samples improved from 28% with acid dissociation to 63% with heat only dissociation. The average DAPI confirmation rate improved from 48% to 85%.