title: Evidence for regular sporulation by Haplosporidium nelsoni (MSX) (Ascetospora; Haplosporidiidae) in spat of the American oyster, Crassostrea virginica.
abstract: The spore stage of Haplosporidium nelsoni, the ascetosporan parasite causing multinucleated sphere unknown (MSX) disease in oysters, Crassostrea virginica, has been reported so rarely (less than 0.01% of infected oysters) that a second host has been postulated. However, recent intensive sampling of young (less than 1 year) oysters in Delaware Bay, U.S. suggests that spore formation occurs regularly in this group and that spores are produced in at least 75-85% of all infections reaching the advanced stage. Sporulation was seasonal, occurring over two to three weeks in late June/early July and again in late summer/early fall. Our data indicate that sporulation by H. nelsoni in oysters is more common than previously suspected, occurring in a segment of the host population that may not have been sufficiently sampled in the past, and that a direct life cycle should be reconsidered.
authors.affiliation: Shellfish Research Laboratory, Rutgers University, Cook College, Port Norris, New Jersey.
authors.forename: R D
authors.initials: RD
authors.lastname: Barber
authors.forename: S A
authors.initials: SA
authors.lastname: Kanaley
authors.forename: S E
authors.initials: SE
authors.lastname: Ford
mesh_terms: D000818:Animals; D016782:Apicomplexa / Q000502:physiology*; D010125:Ostreidae / Q000469:parasitology; D013170:Spores