Virginia Institute of Marine Science
Journal Of Shellfish Research
A haplosporidian parasite, Haplosporidium costale (seaside organism or SSO), is associated with high mortalities of eastern oysters (Crassostrea virginica) in seaside bays of Virginia and Maryland. Its presence in Long Island Sound has been tentatively suggested in several publications for the last 50 y. Positive identification of H. costale and differentiation from another haplosporidian parasite, Haplosporidium nelsoni (MSX), from histological sections is difficult and requires the presence of spores. We detected H. costale spores in 4 out of 5010 (0.08%) oysters collected from Long Island Sound in 1997-1999. In situ hybridization using an oligonucleotide DNA probe designed to detect small subunit ribosomal DNA from Virginia's H. costale reacted positively with tentative H. costale plasmodia in 5 oysters from Long Island Sound. In each case there was a coinfection of H. nelsoni. In Virginia and Maryland, H. costate has historically sporulated in all infected animals in May-June. In Long Island Sound, the rare sporulating cases were detected in October-December, suggesting a different infection cycle.
Haplosporidium Costale; Eastern Oyster; Crassostrea Virginica; In Situ Hybridization; Long Island Sound
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Sunila, I; Stokes, NA; Smolowitz, R; Karney, RC; and Burreson, E. M., "Haplosporidium Costale (Seaside Organism), A Parasite Of The Eastern Oyster, Is Present In Long Island Sound" (2002). VIMS Articles. 472.