Title: New perspectives on virus detection in shellfish: hemocytes as a source of concentrated virus Authors
|Provost, K -|
|Dancho, Brooke -|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 13, 2011
Publication Date: N/A
Technical Abstract: USDA ARS research indicates that circulating phagocytic cells (hemocytes) within oysters retain virus particles. We find that persistence of hepatitis A virus (HAV) within oyster hemocytes correlates with the presence of virus within whole oysters. Since bivalve shellfish have no self-nonself immune recognition, HAV-contaminated hemocytes were transferred to unexposed oysters. Molecular analysis of whole oyster tissues after hemocyte transfer detected HAV 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 acidic 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, MNV, PV, and FCV, respectively. Evaluating the relative resistance of these viruses to low pH exposure indicates that most to least resistant order is HAV> MNV > PV >FCV. Thus, the ability of different enteric viruses to resist acidic inactivation appears to correlate with persistence time within shellfish. We have recently utilized this finding to demonstrate that purifying HAV or murine norovirus RNA directly from hemocytes is an efficient and rapid method for testing shellfish. This test simply involves removing or draining hemocytes from oyster tissues, pelleting, and lysing the pellet and purifying virus RNA using commercial RNA purification kits. We anticipate that this newly developed method will lead to a practical method for routine testing of viruses in shellfish.