Evidence for Regular Sporulation by Haplosporidium nelsoni (MSX) (Ascetospora; Haplosporidiidae) in Spat of the American Oyster, Crassostrea virginica |
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Authors: | ROBERT D BARBER SHEILA A KANALEY SUSAN E FORD |
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Institution: | Shellfish Research Laboratory, Rutgers University, Cook College and the New Jersey Agricultural Experiment Station, P.O. Box 687, Port Norris, New Jersey 08349 |
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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 (≥0.01% of infected oysters) that a second host has been postulated. However, recent intensive sampling of young (≥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. |
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Keywords: | Alternate or reservoir host Ascetospora Haplosporidiidae life cycle protozoa spore |
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