DAO 109:241-250 (2014)  -  DOI: https://doi.org/10.3354/dao02748

Detection of a parasitic amoeba (Order Dactylopodida) in the female gonads of oysters in Brazil

Simone Sühnel1,2,*, Celene da S. Ivachuk1, Ana L. C. Schaefer1, Vitor A. Pontinha1, Maurício L. Martins1, Antonio Figueras3, Gary R. Meyer4, Simon R. M. Jones4, Johnson C. Stewart4, Helen J. Gurney-Smith2, Aimê R. M. Magalhães1, Susan M. Bower

1Nucleus for Aquatic Pathology Studies, Federal University of Santa Catarina (UFSC), Rodovia Admar Gonzaga, 1346, 88040-900, Florianópolis, Santa Catarina (SC), Brazil
2Centre for Shellfish Research, Vancouver Island University, 900 Fifth Street, Nanaimo, British Columbia V9R 5S5, Canada
3Spanish National Reference Laboratory for Molluscs Diseases, Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas (CSIC), Eduardo Cabello 6, 36208 Vigo, Spain
4Pacific Biologic Station, Fisheries and Oceans Canada (DFO), 3190 Hammond Bay Road, Nanaimo, British Columbia V9T 6N7, Canada
*Corresponding author:

ABSTRACT: The impacts of oocyte parasites on the reproductive success of molluscs are largely unknown. In this study, we evaluated the presence of gonad parasites in 6 species of marine bivalve molluscs native to southern Brazil. Cultured bivalves included the mangrove oyster Crassostrea gasar (sometimes called C. brasiliana), the brown mussel Perna perna, the lion’s paw scallop Nodipecten nodosus and the wing pearl oyster Pteria hirundo. Another species of mangrove oyster, C. rhizophorae, and the carib pointed venus clam Anomalocardia brasiliana (syn. A. flexuosa) were collected from the wild. Molluscs were collected in winter 2009 and summer 2010 for histopathological and molecular evaluation. An unknown ovarian parasite (UOP) was observed in histopathological sections of female gonads of C. gasar and C. rhizophorae. The UOP possessed features suggestive of amoebae, including an irregular outer membrane, frothy cytoplasm, a nucleus with a prominent central nucleolus and a closely associated basophilic parasome. PCR analysis was negative for Marteilioides chungmuensis, Perkinsus spp. and Paramoeba perurans. However, real-time PCR successfully amplified DNA from oyster gonads when using universal Paramoeba spp. primers. Also, conventional PCR amplified DNA using primers specific for Perkinsela amoebae-like organisms (syn. Perkinsiella), which are considered as endosymbionts of Parameoba spp., previously thought to be the parasome. Our results suggest that this UOP is a species of amoeba belonging to 1 of the 2 families of the order Dactylopodida, possibly related to Paramoeba spp. This study represents the first report of this type of organism in oysters. We found that C. gasar and C. rhizophorae were the most susceptible molluscs to these UOPs.


KEY WORDS: Oocytes · Ovarian parasite · Marine bivalve · Amoeba


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Cite this article as: Sühnel S, Ivachuk CdS, Schaefer ALC, Pontinha VA and others (2014) Detection of a parasitic amoeba (Order Dactylopodida) in the female gonads of oysters in Brazil. Dis Aquat Org 109:241-250. https://doi.org/10.3354/dao02748

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