TY - JOUR
T1 - Quantitative assessment of viable Cryptosporidium parvum load in commercial oysters (Crassostrea virginica) in the Chesapeake Bay
AU - Graczyk, Thaddeus K.
AU - Lewis, Earl J.
AU - Glass, Gregory
AU - Dasilva, Alexandre J.
AU - Tamang, Leena
AU - Girouard, Autumn S.
AU - Curriero, Frank C.
N1 - Funding Information:
Acknowledgements We apologize for not citing all original articles due to space constrains. We thank Kathy Brohawn, The Maryland Department of the Environment, Baltimore, MD, and John Collier, Oxford, MD, for facilitating this study. The study was supported by the NATO Collaborative Linkage Grant, Brussels, Belgium (grant no. 979765), Johns Hopkins Center in Urban Environmental Health (grant no. P30 ES03819), Alternatives Research & Development Foundation, and NOAA Chesapeake Bay Office (grant no. NA04NMF4570426).
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/1
Y1 - 2007/1
N2 - The epidemiological importance of increasing reports worldwide on Cryptosporidium contamination of oysters remains unknown in relation to foodborne cryptosporidiosis. Thirty market-size oysters (Crassostrea virginica), collected from each of 53 commercial harvesting sites in Chesapeake Bay, MD, were quantitatively tested in groups of six for Cryptosporidium sp. oocysts by immunofluorescent antibody (IFA). After IFA analysis, the samples were retrospectively retested for viable Cryptosporidium parvum oocysts by combined fluorescent in situ hybridization (FISH) and IFA. The mean cumulative numbers of Cryptosporidium sp. oocysts in six oysters (overall, 42.1±4.1) were significantly higher than in the numbers of viable C. parvum oocysts (overall, 28.0±2.9). Of 265 oyster groups, 221 (83.4%) contained viable C. parvum oocysts, and overall, from 10-32% (mean, 23%) of the total viable oocysts were identified in the hemolymph as distinct from gill washings. The amount of viable C. parvum oocysts was not related to oyster size or to the level of fecal coliforms at the sampling site. This study demonstrated that, although oysters are frequently contaminated with oocysts, the levels of viable oocysts may be too low to cause infection in healthy individuals. FISH assay for identification can be retrospectively applied to properly stored samples.
AB - The epidemiological importance of increasing reports worldwide on Cryptosporidium contamination of oysters remains unknown in relation to foodborne cryptosporidiosis. Thirty market-size oysters (Crassostrea virginica), collected from each of 53 commercial harvesting sites in Chesapeake Bay, MD, were quantitatively tested in groups of six for Cryptosporidium sp. oocysts by immunofluorescent antibody (IFA). After IFA analysis, the samples were retrospectively retested for viable Cryptosporidium parvum oocysts by combined fluorescent in situ hybridization (FISH) and IFA. The mean cumulative numbers of Cryptosporidium sp. oocysts in six oysters (overall, 42.1±4.1) were significantly higher than in the numbers of viable C. parvum oocysts (overall, 28.0±2.9). Of 265 oyster groups, 221 (83.4%) contained viable C. parvum oocysts, and overall, from 10-32% (mean, 23%) of the total viable oocysts were identified in the hemolymph as distinct from gill washings. The amount of viable C. parvum oocysts was not related to oyster size or to the level of fecal coliforms at the sampling site. This study demonstrated that, although oysters are frequently contaminated with oocysts, the levels of viable oocysts may be too low to cause infection in healthy individuals. FISH assay for identification can be retrospectively applied to properly stored samples.
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U2 - 10.1007/s00436-006-0261-5
DO - 10.1007/s00436-006-0261-5
M3 - Article
C2 - 16896650
AN - SCOPUS:33845460196
SN - 0932-0113
VL - 100
SP - 247
EP - 253
JO - Parasitology Research
JF - Parasitology Research
IS - 2
ER -