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United States Department of Agriculture

Agricultural Research Service

Title: Detection of Cryptosporidium Oocysts and Giardia Cyst in the Tissues of Eastern Oysters (Crassostrea Virginica) Carring Principal Oyster Infectious Diseases

item Farley, C. - NOAA
item Fayer, Ronald
item Lewis, E. - NOAA
item Trout, James

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 13, 1998
Publication Date: N/A

Interpretive Summary: An immunologic reagent used to detect the protozoan parasites Cryptosporidium parvum and Giardia in environmental samples could cross react with other infectious agents and can lead to incorrect identification. A study involving oysters in the Chesapeake Bay has shown that these filter feeders remove particles, including Cryptosporidium, from the water and can serve as indicators of environmental pollution with human and animal feces. The purpose of the present study was to examine organisms found in oysters with this reagent and to determine if cross reactivity could lead to misidentification. Of 13 organisms examined only 1 demonstrated cross reactivity. That organism (Hexamita) is so physically distinct from Cryptosporidium that the 2 would not be confused. This finding confirms the accuracy of the reagent being used to detect environmental contamination with Cryptosporidium.

Technical Abstract: Combined immunofluorescence antibodies against oocysts and cysts of Cryptosporidium and Giardia, respectively, were examined against oyster tissues containing known developmental stages of 12 protozoan pathogens. Only the trophozoite stage of Hexamita nelsoni produced a positive reaction, indicating that misidentification because of immunologic cross reactivity with this reagent was highly unlikely.

Last Modified: 5/5/2015
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