Enhancement of protozoan pathogen Perkinsus marinus infections in American oysters Crassostrea virginica exposed to the chemical carcinogen n-nitrosodiethylamine (DENA)

Abstract

American oysters Crassostrea virginica exposed to high concentrations (600 mg I-') of nnitrosodiethylamine (DENA) during winter (February to May) showed significant enhancement of an epizootic apicomplexan parasite, Perkinsus rnarinus. The parasite reproduced and caused atypical lesions in exposed oysters in water temperatures at its lower range (20C). The reasons for this enhancement are not clear but may reflect damage to the oysters' nonspecific, cellular defense mechanisms by the DENA without concomitant negative effects on the parasite.