Science Serving Maryland's Coasts

R/ODR-11

A molecular approach to environment studies on Perkinsus marinus. Transmission dynamics of infection in Chesapeake Bay

Principal Investigator: 

Gerardo R. Vasta

Start/End Year: 

1997 to 2000

Institution: 

Center of Marine Biotechnology, University of Maryland Biotechnology Institute

Topic(s): 

Description: 

Our current proposal is focused on continuing the application of our quantitative molecular (PCR) diagnostic techniques for practical field purposes regarding the etiology of this oyster disease in the Chesapeake Bay. This includes the identification of P. marinus strains (Types I and II), Perkinsus species and the certification of disease-free oyster seed. The validation of our PCR-based diagnostic assay and a comparison of its performance with the fluid thioglycollate assay (FTM) revealed not only that the PCR-based diagnostic assay is species-specific and far more sensitive than FTM, but that FTM is not specific for P. marinus FTM detects as positive other Perkinsus spp present in the Chesapeake Bay of yet undetermined virulence for Crassostrea virginica. This represents a serious problem in the assessment of P. marinus infections in natural oyster populations and farmed stocks through the FTM methodology. We propose to (a) optimize our quantitative (competitive) PCR diagnostic assay for C virginica and develop and optimize equivalent competitive PCR tests for the two additional Perkinsus spp present in the Chesapeake Bay in Macoma balthica and Mercenaria mercenaria (b) characterize the genetic, biochemical and physiological aspects of Perkinsus species from C. virginica, M. balthica and M. mercenaria, and assess their host specificity and virulence for C virginica (larval, juvenile and mature), and (c) apply our quantitative PCR assays for the environmental assessment of Perkinsus species in bivalves (C. virginica, M. balthica and M. mercenaria), in the invertebrates associated with oyster reefs, and in the water colurnn.