Host-parasite interactions among broadly distributed populations of the eastern oyster Crassostrea virginica and the protozoan Perkinsus marinus
Allen S Jr
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The protozoan oyster parasite Perkinsus marinus causes extensive mortality in eastern oyster (Crassostrea virginica) populations during summer and fall across much of the oyster's distribution. Despite more than 40 yr of research on this particular parasite, no study has unequivocally demonstrated a genetic basis for host resistance to P. marinus nor has it been determined whether or not there are races of P. marinus that vary in virulence. Using recently developed techniques to culture P. marinus in vitro, we examined the resistance of 4 genetically distinct oyster populations that had different natural histories of exposure to P. marinus and the virulence of 4 geographically distinct isolates of P. marinus. Offspring were produced from each oyster population and reared in a common environment, then exposed to each isolate of P. marinus. Oysters showed levels of resistance roughly corresponding to the duration parental populations had been exposed to P. marinus (Texas > Virginia > New Jersey = Maine), indicating that those populations which have been exposed to P. marinus for more than 40 yr have developed some resistance. Parasites isolated from the Atlantic coast (Mobjack Bay, VA and Delaware Bay, NJ, USA) produced heavier infections than those isolated from the Gulf of Mexico coast (Barataria Bay, LA and South Bay Laguna Madre, TX, USA), indicating that Atlantic isolates were more virulent than Gulf isolates. These data indicate that resistant races of the eastern oyster exist, and imply the existence of virulent parasite races. No statistically significant interaction was detected between oyster populations and parasite isolates. Relative infection intensities among oyster populations remained more or less constant across parasite isolates and vice versa. The lack of a significant interaction between host populations and parasite isolates indicated that mechanisms of resistance and virulence were general, not race-specific
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Dermowatch: A new tool for managing Perkinsus marinus disease in Eastern Oysters, Crassostrea virginica Soniat TM; Kortright EV; Ray SM (, 2000 200)A website called DermoWatch has been established (www.blueblee.com/dermo) to track the progression of Perkinsus marinus (= Dermocystidium marinum) in Galveston Bay and allow users from other locations to also calculate a ...
Ray SM; Soniat TM (, 2003 200)DermoWatch is a web site (www.blueblee.com/dermo), a monitoring program and an online community for the management of the oyster parasite, Perkinsus marinus. The web site contains an embedded model, which calculates a time ...
Ray SM; Soniat TM; Kortright EV (, 2001 200)A web site called Dermo Watch (www.blueblee.com/dermo) has been established to help manage Perkinsus marinus (= Dermocystidium marinum) disease of eastern oysters, Crassostrea virginica. The main page provides the most ...