Novotny L, Powers C M, Royal S M, Preston A K, Hendrix G K, Sola M F
Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA.
Aquaculture Research Laboratory, Purdue University, West Lafayette, Indiana, USA.
J Aquat Anim Health. 2024 Dec;36(4):303-309. doi: 10.1002/aah.10231. Epub 2024 Dec 2.
The hellbender Cryptobranchus alleganiensis is a fully aquatic, long-lived, and state endangered salamander endemic to the eastern and central United States. Chytridiomycosis is a fungal skin disease of salamanders that can be caused by either Batrachochytrium dendrobatidis (Bd) or by recently described B. salamandrivorans. B. salamandrivorans is responsible for massive mortality of salamanders in Europe but, to date, has not been reported in the United States, in contrast to Bd. Common signs of Bd infection in salamanders are excessive skin shedding; cutaneous discoloration; mainly in ventral parts of the abdomen and thighs; and eventually death as a result of osmotic imbalance.
Eastern hellbenders C. a. alleganiensis in the Aquaculture Research Laboratory at Purdue University experienced 33% mortality. Three of the deceased animals were autopsied, and samples for histopathology, microbiology, and Taqman quantitative polymerase chain reaction were taken.
Autopsy revealed an abundant, thick, yellow to green mucoid material on the surface of the skin, mainly on the tail and flanks. Histopathology of the skin samples revealed infection with chytrid fungus consistent with chytridiomycosis. Taqman quantitative polymerase chain reaction confirmed presence of Bd, and bacterial culture confirmed co-infection with Aeromonas hydrophila. Infected hellbenders were treated with ciprofloxacin, itraconazole, and ceftazidime.
The chytridiomycosis outbreak was most likely caused by sudden environmental stress due to filtration failure and secondary bacterial infection. The surviving animals have not shown any clinical signs of chytridiomycosis for more than 1 year after the treatment and were released the wild river system.
隐鳃鲵是一种完全水生、寿命长且为美国东部和中部特有的濒危蝾螈。蛙壶菌病是蝾螈的一种真菌性皮肤病，可由蛙壶菌（Bd）或最近发现的蝾螈壶菌引起。蝾螈壶菌导致了欧洲蝾螈的大量死亡，但迄今为止，与蛙壶菌不同，在美国尚未有相关报道。蝾螈感染蛙壶菌的常见症状包括皮肤过度脱落；皮肤变色，主要在腹部和大腿的腹侧部位；最终因渗透失衡而死亡。
普渡大学水产养殖研究实验室的东部隐鳃鲵死亡率为33%。对3只死亡动物进行了尸检，并采集了用于组织病理学、微生物学和Taqman定量聚合酶链反应的样本。
尸检发现皮肤表面有大量、浓稠、黄色至绿色的黏液物质，主要在尾部和体侧。皮肤样本的组织病理学显示感染了与蛙壶菌病相符的壶菌真菌。Taqman定量聚合酶链反应证实存在蛙壶菌，细菌培养证实同时感染了嗜水气单胞菌。对感染的隐鳃鲵用环丙沙星、伊曲康唑和头孢他啶进行了治疗。
蛙壶菌病的爆发很可能是由于过滤故障导致的突然环境压力和继发性细菌感染引起的。存活的动物在治疗后1年多未表现出任何蛙壶菌病的临床症状，并被放归到野生河流系统中。
