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AWWA WQTC69504
- Cryptosporidium off-the-Slide Genotyping: Recovery of Oocysts Extracted from Slides Examined by Method 1623
- Conference Proceeding by American Water Works Association, 11/01/2008
- Publisher: AWWA
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This study focuses on recovery efficiencies of whole Cryptosporidium parvum oocysts using "off-the-slide"extraction techniques. The extraction approach was evaluated in two phases: removalof the coverslip and mounting media; and, transfer of the oocysts from the slide to thegenotyping tube. C. parvum oocysts were counted by flow cytometry to contain 200, 20 or 0oocysts per well. The coverslip was then removed and retained, and the well was washed. Thecoverslip and washed well were recounted. Results show that the number of oocysts remainingon the well was variable after removal of the coverslip and mounting media, ranging from nearly50% to 95%. Less than 2% of the oocysts on average were attached to the coverslip, with theremaining oocysts removed with the mounting media. These results suggest that removal of thecoverslip accounts for little oocyst loss; however, the mounting media retained on the slide mustbe transferred to the genotyping tube to accurately reflect the oocysts on the slide. Includes 8 references, abstract only.