Disseminated Phaeohyphomycosis in Weedy Seadragons (Phyllopteryx Taeniolatus) and Leafy Seadragons (Phycodurus Eques) Caused by Species of Exophiala, Including a Novel Species

Abstract

Abstract. During the period from January 2002 to March 2007, infections by melanized fungi were identified with greater frequency in aquarium-maintained leafy seadragons (Phycodurus eques) and weedy seadragons (Phyllopteryx taeniolatus), pivotal species to the educational and environmental concerns of the aquarium industry and conservation groups. The objective of this study was to characterize the pathology and identify fungi associated with phaeohyphomycotic lesions in these species. Samples from 14 weedy and 6 leafy seadragons were received from 2 institutions and included fresh, frozen, and formalin-fixed tissues from necropsy and biopsy specimens. Fresh and frozen tissues were cultured for fungi on Sabouraud dextrose agar only or both Sabouraud dextrose agar and inhibitory mold agar with gentamicin and chloramphenicol at 30uC. Isolates were processed for morphologic identification and molecular sequence analysis of the internal transcribed spacer region and D1/D2 domains of the large subunit ribosomal RNA gene. Lesions were extensive and consisted of parenchymal and vascular necrosis with fungal invasion of gill (11/20), kidney (14/20), and other coelomic viscera with or without cutaneous ulceration (13/20). Exophiala sp. isolates were obtained from 4 weedy and 3 leafy seadragons and were identified to species level in 6 of 7 instances, namely Exophiala angulospora (1) and a novel species of Exophiala (5), based on nucleotide sequence comparisons and phylogenetic analyses. Disseminated phaeohyphomycosis represents an important pathologic condition of both weedy and leafy seadragons for which 2 species of Exophiala, 1 a novel species, have been isolated.

Phaeohyphomycoses, Emerging Opportunistic Diseases in Animals

“…Disseminated infections by Exophiala angulospora were identified repeatedly in aquarium-maintained weedy seadragons (Phyllopteryx taeniolatus) (38). A novel species of Exophiala, now described as E. aquamarina, caused infections in leafy seadragons (Phycodurus eques).…”

Dermatitis and systemic mycosis in lined seahorses Hippocampus erectus associated with a marine-adapted Fusarium solani species complex pathogen

“…Uronema marinum and the microsporidian Glugea heraldi have also been described in syngnathids but have limited to no treatment options, respectively (Koldewey 2005). Significant diseases include mycobacteriosis and Vibrio harveyi septicemia, and fungal exophilalosis (Blazer & Wolke 1979, Koldewey 2005, Nyaoke et al 2009). Herein we report on the gross and histopathologic findings associated with an epizootic of fusariosis in a group of lined seahorses, as well as the molecular identification and phylogenetic characterization of the agent as an unnamed phylogenetic species designated FSSC 12-a Fusarium sp.…”

Pathologic Findings in Weedy (Phyllopteryx taeniolatus) and Leafy (Phycodurus eques) Seadragons

“…19 The lesions consisted of areas of vascular and fibrinoid parenchymal necrosis and granulocytic and histiocytic inflammation with numerous thin-walled, septate fungal hyphae that stain brown in routine HE sections (Fig. 9).…”

“…5,8,19,23 Most cases of phaeohyphomycosis were diagnosed by morphology and staining characteristics on light microscopy, although several cases included here were diagnosed by culture and sequencing of PCR-amplified DNA. 19 Similarly, intestinal coccidiosis has been reported to be caused by a novel species of Eimeria in the WSD (Eimeria phyllopterycis). 20,27 Although intestinal coccidiosis was reported in 5 WSD in this study, no cases were found in LSD, which is consistent with the findings in another report.…”