Name
Chromomycosis due to Veronaea botryosa in a Tiger Salamander (Ambystoma tigrinum)
Date & Time
Monday, August 26, 2024, 1:00 PM - 1:40 PM
Description

A research population of captive-bred, individually housed tiger salamanders presented with chronic “cysts” progressing to tumor-like cutaneous swellings over the dorsal midline extending caudally from the neck. Antemortem skin impression smears and scrapes performed on two, approximately 4-year-old female tiger salamanders contained abundant, mixed bacteria including Gram-positive, acid-fast negative, and Gram-negative rods, with phagocytosis by histiocytes. The most severely affected individual was euthanized, necropsied, and had a well-defined and irregularly marginated region of dark discoloration and roughened surface along the dorsal midline with multifocal, soft, pale pink, solid dermal to subcutaneous nodules. Microscopically, the dermis and underlying skeletal muscle were disrupted by nodular, densely cellular populations of epithelioid macrophages, multinucleated giant cells, and fewer eosinophils with foci of necrosis. Individual and clustered pigmented muriform cells and rare hyphae were scattered intracellularly and extracellularly within the inflammation and necrosis. Muriform cells were round and approximately 9-12 μm in diameter with a thin, darkly pigmented capsule, central, foamy, clear to lightly basophilic cytoplasm, and occasionally a midline division. Fungal culture yielded a pigmented fungus that was molecularly confirmed as Veronaea botryosa with 100% similarity across ~600 bp of the internal transcribed spacer 1-2 region. Chromomycosis is a chronic disease caused by cutaneous or subcutaneous inoculation with pigmented fungi. Multiple pigmented fungal species cause chromomycosis in amphibians. Infection with the zoonotic pathogen Veronaea botryosa has been reported in anurans including White’s tree frogs, false tomato frogs, and eastern-Japanese common toads, but this is the first detection in a urodelian host to our knowledge.

Location Name
Exhibit Hall
Full Address
New Orleans Marriott
555 Canal St
New Orleans, LA 70130
United States
Session Type
Poster