Submitted to: American Society of Parasitologists
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 1998
Publication Date: N/A
Thirty oysters, Crassostrea virginica, from the Maryland portion of Chesapeake Bay were collected by the state's shellfish health program from each of 5 commercial oyster bars in tributaries of the Bay in Oct and Nov 1997. Sites in the Wicomico, Nanticoke, Potomac and Patuxent Rivers and in Fishing Bay were designated A-E, respectively. Within 3 days of collection hemolymph was aspirated from the adductor muscle and gifts were excised and washed in PBS to remove associated particulate matter. Hemolymph and gill wash sediment from each oyster was dried onto glass microscope slides and stained with immunofluorescence reagents to detect oocysts of Cryptosporidium. Fluorescein labeled oocysts 4-6um in diameter were identified in 28, 29, 26, 29 and 29, or 30 oysters from sites A-E, respectively. Hemolymph or gill washings from 6 oysters at each site were pooled, held at 5 degree C until slides were examined, and pools from oysters with the most oocysts were selected for PCR analysis. The presence of Cryptosporidium oocysts in oysters at sites B and E was confirmed using PCR for TRAP 2 and beta-tubulin raises concern as to the source of oocysts contaminating the waters from which the oysters were collected and concern of potential foodborne infection for persons eating raw or undercooked oysters. (Supported in part by Maryland Sea Grant R/F-88).