title: Dermatitis and systemic mycosis in lined seahorses Hippocampus erectus associated with a marine-adapted Fusarium solani species complex pathogen.
abstract: During a 4 mo epizootic, 100% of 152 lined seahorses Hippocampus erectus in 3 separate groups died while in quarantine following shipment to a public aquarium. Twelve animals with skin depigmentation and ulceration were received by the Aquatic Pathology Service, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA, for diagnostic evaluation. Microscopically, lesions in 11 seahorses included multifocal epithelial necrosis and ulceration associated with 2 to 7 µm diameter, branching, septate fungal hyphae, typically accompanied by deeper infiltration into underlying skeletal muscle. Angioinvasion, with vascular thrombosis and tissue infarction, was a prominent feature in multiple animals. Fungal invasion of one or more internal organs was observed in 4 animals. Hyphae appeared to course freely through tissues and elicited little or no inflammatory response. Fusariosis has been reported sporadically in fish and other aquatic organisms, but identification has often been limited to the genus level based solely on morphologic features. Morphologic characteristics of the fungus isolated from this case were consistent with the Fusarium solani species complex (FSSC), which includes over 50 members that can only be identified definitively using DNA sequence data. A 3-locus typing scheme identified the isolate as a distinct species/haplotype, designated FSSC 12-a, belonging to a specific lineage that appears adapted to aquatic environments and disease in marine animals. Empirical treatment with itraconazole failed to stop mortalities, and subsequent in vitro antifungal susceptibility data explained a lack of clinical efficacy for this agent. Effective treatment in human medicine has similarly been limited by poor susceptibility to several classes of antifungal compounds.
authors.affiliation: Department of Pathology, The University of Georgia College of Veterinary Medicine, Athens, Georgia 30602, USA.
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Salter
authors.forename: Kerry
authors.initials: K
authors.lastname: O'Donnell
authors.forename: Deanna A
authors.initials: DA
authors.lastname: Sutton
authors.forename: David P
authors.initials: DP
authors.lastname: Marancik
authors.forename: Susan
authors.initials: S
authors.lastname: Knowles
authors.forename: Tonya M
authors.initials: TM
authors.lastname: Clauss
authors.forename: Aimee L
authors.initials: AL
authors.lastname: Berliner
authors.forename: Alvin C
authors.initials: AC
authors.lastname: Camus
mesh_terms: D000818:Animals; D001483:Base Sequence; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D004196:Disease Outbreaks; D005393:Fish Diseases / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology; D060585:Fusariosis / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D005670:Fusarium / Q000235:genetics / Q000254:growth & development*; D006651:Histocytochemistry; D008969:Molecular Sequence Data; D010473:Perciformes; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer