Clams ( Corbicula fluminea) as bioindicators of fecal contamination with Cryptosporidium and Giardia spp. in freshwater ecosystems in California
This study evaluated clams as bioindicators of fecal protozoan contamination using three approaches: (i) clam tissue spiking experiments to compare several detection techniques; (ii) clam tank exposure experiments to evaluate clams that had filtered Cryptosporidium oocysts from inoculated water unde...
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Published in | International journal for parasitology Vol. 35; no. 6; pp. 673 - 684 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Elsevier Ltd
01.05.2005
Elsevier Science |
Subjects | |
Online Access | Get full text |
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Summary: | This study evaluated clams as bioindicators of fecal protozoan contamination using three approaches: (i) clam tissue spiking experiments to compare several detection techniques; (ii) clam tank exposure experiments to evaluate clams that had filtered
Cryptosporidium oocysts from inoculated water under a range of simulated environmental conditions; (iii) sentinel clam outplanting to assess the distribution and magnitude of fecal contamination in three riverine systems in California. Our spiking and tank experiments showed that direct fluorescent antibody (DFA), immunomagnetic separation (IMS) in combination with DFA, and PCR techniques could be used to detect
Cryptosporidium in clam tissues. The most analytically sensitive technique was IMS concentration with DFA detection of oocysts in clam digestive gland tissues, which detected 10 oocysts spiked into a clam digestive gland 83% of the time. In the tank experiment, oocyst dose and clam collection time were significant predictors for detecting
Cryptosporidium parvum oocysts in clams. In the wild clam study,
Cryptosporidium and
Giardia were detected in clams from all three study regions by IMS-DFA analysis of clam digestive glands, with significant variation by sampling year and season. The presence of
C. parvum DNA in clams from riverine ecosystems was confirmed with PCR and DNA sequence analysis. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0020-7519 1879-0135 |
DOI: | 10.1016/j.ijpara.2005.01.002 |