DAO 104:13-21 (2013)  -  DOI: https://doi.org/10.3354/dao02586

Epitheliocystis hyperinfection in captive spotted eagle rays Aetobatus narinari associated with a novel Chlamydiales 16S rDNA signature sequence

Alvin Camus1,*, Esteban Soto2, Aimee Berliner3, Tonya Clauss3, Susan Sanchez4

1Department of Pathology and 4Athens Veterinary Diagnostic Laboratory and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602, USA
2Department of Pathobiology, School of Veterinary Medicine, Ross University, Basseterre, St. Kitts, West Indies
3Department of Veterinary Services, Georgia Aquarium Inc., 225 Baker Street NW, Atlanta, Georgia 30313, USA
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ABSTRACT: This report details 2 cases of epitheliocystis in spotted eagle rays Aetobatus narinari associated with a novel Chlamydiales 16S rDNA signature sequence. Epitheliocystis is a common disease of variable severity affecting >50 species of wild and cultured freshwater and marine teleosts. Disease in elasmobranchs is rarely reported and descriptions are limited. Occurring in gill and skin epithelium, lesions are characterized by large hypertrophied cells with basophilic inclusions containing Gram-negative, chlamydia-like bacteria. Acute lethargy, labored respiration, and abnormal swimming developed in a captive spotted eagle ray following an uneventful quarantine period, and mild epitheliocystis lesions were found microscopically. Three months later, a second animal exhibited similar signs. A gill clip revealed myriad spherical bodies identical to the previous case, and treatment with chloramphenicol and oxytetracycline was initiated. Despite therapy, respiration became irregular and euthanasia was elected. Histologically, epitheliocystis inclusions up to 200 µm filled approximately 80% of lamellar troughs. Multifocal mild hypertrophy and hyperplasia of lamellar tips was accompanied by mild to moderate infiltrates of granulocytes and lymphocytes. Electron microscopy revealed a homogeneous population of elongate chlamydia-like bacterial forms similar in size and morphology to the primary long cells described in teleosts. Immunohistochemical staining with a polyclonal anti-chlamydial lipopolysaccharide antibody was positive. Sequence analysis of a unique 296 bp Chlamydiales signature sequence amplicon isolated from the rays showed greatest homology (85 to 87%) to ‘Candidatus Piscichlamydia salmonis’.


KEY WORDS: Elasmobranch · Epithelium · Lesion · Hypertrophy · ‘Candidatus Piscichlamydia salmonis’ · Immunohistology · Diagnosis


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Cite this article as: Camus A, Soto E, Berliner A, Clauss T, Sanchez S (2013) Epitheliocystis hyperinfection in captive spotted eagle rays Aetobatus narinari associated with a novel Chlamydiales 16S rDNA signature sequence. Dis Aquat Org 104:13-21. https://doi.org/10.3354/dao02586

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