This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fayer, R. Articles by Farley, C. A. Search for Related Content PubMed PubMed Citation Articles by Fayer, R. Articles by Farley, C. A. Agricola Articles by Fayer, R. Articles by Farley, C. A.

 Previous Article  |  Next Article 

Appl Environ Microbiol, March 1998, p. 1070-1074, Vol. 64, No. 3
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Survival of Infectious Cryptosporidium parvum Oocysts in Seawater and Eastern Oysters (Crassostrea virginica) in the Chesapeake Bay

Ronald Fayer,^1,* Thaddeus K. Graczyk,² Earl J. Lewis,³ James M. Trout,¹ and C. Austin Farley³

Immunology and Disease Resistance Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705-2350¹; Department of Molecular Microbiology and Immunology, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205-2179²; and Cooperative Oxford Laboratory, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Oxford, Maryland 21654-9724³

Received 20 October 1997/Accepted 23 December 1997

Oocysts of Cryptosporidium parvum placed in artificial seawater at salinities of 10, 20, and 30 ppt at 10°C and at 10 ppt at 20°C were infectious after 12 weeks. Those placed in seawater at 20 ppt and 30 ppt at 20°C were infectious for 8 and 4 weeks, respectively. These findings suggested that oocysts could survive in estuarine waters long enough to be removed by filter feeders such as oysters. Thereafter, 30 Eastern oysters, Crassostrea virginica, were collected with a dredge or with hand tongs at each of six sites within Maryland tributaries of the Chesapeake Bay in May and June and in August and September of 1997. Hemocytes and gill washings from all oysters were examined for the presence of Cryptosporidium oocysts and Giardia cysts by immunofluorescence microscopy utilizing a commercially available kit containing fluorescein isothiocyanate-conjugated monoclonal antibodies. Giardia was not detected by this method from any of the 360 oysters examined. Presumptive identification of Cryptosporidium oocysts was made in either hemocytes or gill washings of oysters from all six sites both times that surveys were conducted. In addition, during August and September, for each of the six sites, hemocytes from the 30 oysters were pooled and gill washings from the oysters were pooled. Each pool was delivered by gastric intubation to a litter of neonatal mice to produce a bioassay for oocyst infectivity. Intestinal tissue from two of three mice that received gill washings from oysters collected at a site near a large cattle farm and shoreline homes with septic tanks was positive for developmental stages of C. parvum. These findings demonstrate for the first time that oysters in natural waters harbor infectious C. parvum oocysts and can serve as mechanical vectors of this pathogen.

---

^* Corresponding author. Mailing address: Immunology and Disease Resistance Laboratory, Agricultural Research Service, U.S. Department of Agriculture, 10300 Baltimore Avenue, Building 1040, Beltsville, MD, 20705-2350. Phone: 301-504-8750. Fax: 301-504-5306. E-mail: rfayer{at}ggpl.arsusda.gov.

This article has been cited by other articles:

• Downey, A. S., Graczyk, T. K. (2007). Maximizing Recovery and Detection of Cryptosporidium parvum Oocysts from Spiked Eastern Oyster (Crassostrea virginica) Tissue Samples. Appl. Environ. Microbiol. 73: 6910-6915 [Abstract] [Full Text]  
• Sunnotel, O., Snelling, W. J., McDonough, N., Browne, L., Moore, J. E., Dooley, J. S. G., Lowery, C. J. (2007). Effectiveness of Standard UV Depuration at Inactivating Cryptosporidium parvum Recovered from Spiked Pacific Oysters (Crassostrea gigas). Appl. Environ. Microbiol. 73: 5083-5087 [Abstract] [Full Text]  
• Graczyk, T. K., Girouard, A. S., Tamang, L., Nappier, S. P., Schwab, K. J. (2006). Recovery, Bioaccumulation, and Inactivation of Human Waterborne Pathogens by the Chesapeake Bay Nonnative Oyster, Crassostrea ariakensis.. Appl. Environ. Microbiol. 72: 3390-3395 [Abstract] [Full Text]  
• Traversa, D., Giangaspero, A., Molini, U., Iorio, R., Paoletti, B., Otranto, D., Giansante, C. (2004). Genotyping of Cryptosporidium Isolates from Chamelea gallina Clams in Italy. Appl. Environ. Microbiol. 70: 4367-4370 [Abstract] [Full Text]  
• Xiao, L., Singh, A., Limor, J., Graczyk, T. K., Gradus, S., Lal, A. (2001). Molecular Characterization of Cryptosporidium Oocysts in Samples of Raw Surface Water and Wastewater. Appl. Environ. Microbiol. 67: 1097-1101 [Abstract] [Full Text]  
• Gomez-Bautista, M., Ortega-Mora, L. M., Tabares, E., Lopez-Rodas, V., Costas, E. (2000). Detection of Infectious Cryptosporidium parvum Oocysts in Mussels (Mytilus galloprovincialis) and Cockles (Cerastoderma edule). Appl. Environ. Microbiol. 66: 1866-1870 [Abstract] [Full Text]  
• Kuczynska, E., Shelton, D. R. (1999). Method for Detection and Enumeration of Cryptosporidium parvum Oocysts in Feces, Manures, and Soils. Appl. Environ. Microbiol. 65: 2820-2826 [Abstract] [Full Text]  
• Graczyk, T. K., Fayer, R., Trout, J. M., Lewis, E. J., Farley, C. A., Sulaiman, I., Lal, A. A. (1998). Giardia sp. Cysts and Infectious Cryptosporidium parvum Oocysts in the Feces of Migratory Canada Geese (Branta canadensis). Appl. Environ. Microbiol. 64: 2736-2738 [Abstract] [Full Text]