Survey of Potential Reservoir Species for the Oyster Parasite Multinucleate Sphere X (Haplosporidium nelsoni) in and Around Oyster Farms in the Damariscotta River Estuary, Maine

Abstract

ABSTRACT In the summer of 2010, the Damariscotta River Estuary, ME, experienced the first large multinucleate sphere X disease (Haplosporidium nelsoni) outbreak in commercial stocks of the eastern oyster (Crassostrea virginica). In 2012, biofouling organisms were sampled in and around the commercial oyster operations with the intent of looking for the presence of the parasite to see which, if any, biofouling species may be acting as a reservoir host and harboring the parasite. Organisms collected included tunicates, gastropods, polychaetes, and arthropods, as well as plankton samples from the surrounding water column. A quantitative polymerase chain reaction assay for H. nelsoni using a TaqMan minor groove binder probe, which was originally developed for detection of the parasiteDNAin oysters, was applied to biofouling species. The protozoan parasite H. nelsoniDNA was present in up to 70% of tunicate samples and about 30% of plankton samples. The highest parasite DNA copies (averaging 4 × 104 copies) were...