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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: A Potential Mechanism of Virus Persistence within Bivalve Shellfish.

Authors
item Kingsley, David
item Provost, Keleigh -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 21, 2010
Publication Date: July 21, 2010
Citation: Kingsley,D.,Provost,K. 2010.A Potential Mechanism of Virus Persistance within Bivalve Shellfish [abstract].American Society of Virology.Bozeman,Montana.p.1.

Technical Abstract: The process of enteric virus bioaccumulation by molluscan shellfish has been widely studied and documented. However, it is not understood why some human enteric viruses, which cannot replicate within shellfish, are selectively retained and remain viable within shellfish tissues for extended periods. Researching this question, we found multiple lines of experimental evidence that suggest phagocytic hemocytes as a site of virus persistence within live bivalves. First, persistence of hepatitis A virus (HAV) within oyster hemocytes (blood cells) correlates with the presence of virus within whole oysters. Also 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 were transferred to unexposed oysters. Analysis of whole oyster tissues detected HAV by RT-PCR 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, they would likely be sequestered within low pH endo-lysosomal vesicles within these cells. Examination of temporal persistence of four different viruses within oysters was examined. The longest to shortest duration of persistence within oysters, as judged by RT-PCR analysis, was HAV, PV, murine norovirus (MNV), and feline calicivirus (FCV), respectively. Evaluating the relative resistance of these viruses to low pH exposure, indicates that the most to least resistant order is HAV>PV>MNV>FCV. Thus, the ability of different enteric viruses’ to persist within an acidic environment appears to correlate with long term persistence in shellfish.

Last Modified: 9/23/2014
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