DAO 47:63-72 (2001)  -  doi:10.3354/dao047063

Bonamia exitiosus n.sp. (Haplosporidia) infecting flat oysters Ostrea chilensis in New Zealand

P. M. Hine1,*, N. Cochennec-Laureau2, F. C. J. Berthe2

1National Institute of Water and Atmospheric Research, PO Box 14-901, Kilbirnie, Wellington, New Zealand
2IFREMER, Laboratoire de Génétique et Pathologie, BP 133, Ronce-les Bains, La Tremblade 17390, France
*Present address: Aquatic Animal Diseases, National Centre for Disease Investigation, MAF Operations, PO Box 40-742, Upper Hutt, New Zealand. E-mail:

ABSTRACT: Bonamia sp. is a pathogenic parasite that occurs in the haemocytes of dredge oysters Ostrea chilensis Philippi in New Zealand. Ultrastructurally it resembles other haplosporidians in the possession of haplosporosomes, haplosporogenesis, persistence of mitotic microtubules during interphase and of the nuclear envelope during mitosis, and occurrence of a diplokaryotic or multi-nucleate plasmodial stage. Another stage containing a large vacuole derived from enlargement of 1 or more mitochondria has not previously been described from other haplosporidians. It most closely resembles B. ostreae Pichot et al., 1979, which parasitises and is pathogenic in haemocytes of European flat oysters, O. edulis. However, B. ostreae is smaller and denser, and has fewer lipoid bodies and haplosporosomes. We have nearly completely sequenced the small ribosomal gene of the organism from O. chilensis. Initial comparisons of these sequences with those of other protozoans showed similarities to B. ostreae. Polymorphism within Bonamia sp. was confirmed by restriction fragment length polymorphism analysis. On the basis of ultrastructural and molecular considerations it is proposed that this organism be named Bonamia exitiosus sp. nov.

KEY WORDS: Bonamia exitiosus · Ostrea chilensis · Ultrastructure · 18S rDNA · New Zealand

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