DAO 127:1-9 (2017)  -  DOI: https://doi.org/10.3354/dao03175

Partial 18S rRNA sequences of apicomplexan parasite ‘X’ (APX), associated with flat oysters Ostrea chilensis in New Zealand

Nguyen Thao Suong1,2,*, Stephen Webb2, Jonathan Banks2, Kevin C. Wakeman4,5, Henry Lane3, Andrew Jeffs1, Cara Brosnahan3, Brian Jones3, Andrew Fidler

1Institute of Marine Science, University of Auckland, Auckland 1142, New Zealand
2Cawthron Institute, Nelson 7010, New Zealand
3Ministry for Primary Industries, Wallaceville, Upper Hutt 5018, New Zealand
4Office of International Affairs, Hokkaido University, Sapporo 060-0810, Japan
5Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
*Corresponding author:

ABSTRACT: Apicomplexa is a large phylum of parasitic protists renowned for significant negative health impacts on humans and livestock worldwide. Despite the prevalence and negative impacts of apicomplexans across many animal groups, relatively little attention has been given to apicomplexan parasites of invertebrates, especially marine invertebrates. Previous work has reported an apicomplexan parasite ‘X’ (APX), a parasite that has been histologically and ultrastructurally identified from the commercially important flat oyster Ostrea chilensis in New Zealand. This apicomplexan may exacerbate host vulnerability to the infectious disease bonamiosis. In this study, we report 18S rRNA sequences amplified from APX-infected O. chilensis tissues. Phylogenetic analyses clearly established that the 18S sequences were of apicomplexan origin; however, their detailed relationship to known apicomplexan groups is less resolved. Two specific probes, designed from the putative APX 18S rRNA sequence, co-localised with APX cells in in situ hybridisations, further supporting our hypothesis that the 18S sequences were from APX. These sequences will facilitate the future development of inexpensive and sensitive molecular diagnostic tests for APX, thereby assisting research focussed on the biology and ecology of this organism and its role in morbidity and mortality of O. chilensis.


KEY WORDS: APX zoites · Molecular identification · Shellfish disease · In situ hybridisation


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Cite this article as: Suong NT, Webb S, Banks J, Wakeman KC and others (2017) Partial 18S rRNA sequences of apicomplexan parasite ‘X’ (APX), associated with flat oysters Ostrea chilensis in New Zealand. Dis Aquat Org 127:1-9. https://doi.org/10.3354/dao03175

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