Phaeohyphomycosis due to <i>Exophiala</i> in Aquarium-Housed Lumpfish (<i>Cyclopterus lumpus</i>): Clinical Diagnosis and Description

oleh: Colin T. McDermott, Charles J. Innis, Akinyi C. Nyaoke, Kathryn A. Tuxbury, Julie M. Cavin, E. Scott Weber, Deana Edmunds, Stéphane Lair, Jill V. Spangenberg, Amy L. Hancock-Ronemus, Catherine A. Hadfield, Leigh A. Clayton, Thomas B. Waltzek, Connie F. Cañete-Gibas, Nathan P. Wiederhold, Salvatore Frasca

Format: Article
Diterbitkan: MDPI AG 2022-11-01

Deskripsi

Phaeohyphomycosis caused by <i>Exophiala</i> species represents an important disease of concern for farmed and aquarium-housed fish. The objective of this study was to summarize the clinical findings and diagnosis of <i>Exophiala</i> infections in aquarium-housed <i>Cyclopterus lumpus</i>. Clinical records and postmortem pathology reports were reviewed for 15 individuals from 5 public aquaria in the United States and Canada from 2007 to 2015. Fish most commonly presented with cutaneous ulcers and progressive clinical decline despite topical or systemic antifungal therapy. Antemortem fungal culture of cutaneous lesions resulted in colonial growth for 7/12 samples from 8 individuals. Amplification of the internal transcribed spacer region (ITS) of nuclear rDNA identified <i>Exophiala angulospora</i> or <i>Exophiala aquamarina</i> in four samples from three individuals. Postmortem histopathologic findings were consistent with phaeohyphomycosis, with lesions most commonly found in the integument (11/15), gill (9/15), or kidney (9/15) and evidence of fungal angioinvasion and dissemination. DNA extraction and subsequent ITS sequencing from formalin-fixed paraffin-embedded tissues of seven individuals identified <i>E. angulospora, E. aquamarina</i>, or <i>Cyphellophora</i> sp. in four individuals. Lesion description, distribution, and <i>Exophiala</i> spp. identifications were similar to those reported in farmed <i>C. lumpus</i>. Antemortem clinical and diagnostic findings of phaeohyphomycosis attributable to several species of <i>Exophiala</i> provide insight on the progression of <i>Exophiala</i> infections in lumpfish that may contribute to management of the species in public aquaria and under culture conditions.