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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR & BIOCHEMICAL DETECTION & INTERVENTION METHODS FOR BACTERIAL AND VIRAL PATHOGENS IN AQUACULTURE PRODUCTS

Location: Food Safety and Intervention Technologies

Title: Persistence of enteric viruses within oysters (Crassostrea virginica)

Author
item Kingsley, David

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 16, 2010
Publication Date: September 16, 2010
Citation: Kingsley, D. 2010. Persistance of enteric viruses within oysters (Crassostrea virginica) [abstract].Interstate Seafood Seminar.Ocean City,MD.p.1.

Technical Abstract: It is well known that water-borne enteric viruses are concentrated by bivalves. Why these viruses are selectively retained and remain infectious within shellfish tissues for extended periods is unknown. Our current hypothesis is that phagocytic hemocytes (blood cells) are a site of virus persistence within live bivalves. Evidence for this is multi-fold. We find that persistence of hepatitis A virus (HAV) within oyster hemocytes correlates with the presence of virus within whole oysters and viable HAV and poliovirus (PV) have been isolated from hemocytes after exposure of live oysters to HAV- and PV-contaminated water. Since bivalve shellfish have no self-nonself immune recognition, HAV-contaminated hemocytes can be transferred to unexposed oysters. Analysis of whole oyster tissues after hemocyte transfer detected HAV by molecular analysis for up to two weeks after transfer of hemocytes from HAV-exposed oysters to non-HAV-exposed oysters. Further, if viruses are phagocytized by hemocytes, viruses should be localized within low pH endo-lysosomal vesicles within these cells. Examination of persistence times for different viruses within oysters was examined. The longest to shortest duration of persistence within oysters, as judged by RT-PCR analysis, was HAV, PV, MNV, and FCV, respectively. Evaluating the relative resistance of these viruses to low pH exposure, indicates that most to least resistant order is HAV>PV>MNV>FCV. Thus, the ability of different enteric viruses to resist an acidic inactivation appears to correlate with persistence time within shellfish.

Last Modified: 7/22/2014