Fogelson S B, Fast M D, Leary J, Camus A C
Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
Department of Pathology and Microbiology, University of Prince Edward Island, Atlantic Veterinary College, Charlottetown, PE, Canada.
J Fish Dis. 2017 Nov;40(11):1681-1694. doi: 10.1111/jfd.12634. Epub 2017 Apr 27.
Syngnathidae (seahorses, seadragons and pipefish) suffer significant losses from non-tuberculous mycobacteria. However, they produce markedly different lesions in response to the disease compared to other teleost species, notably infrequent granuloma formation. This study evaluated 270 syngnathid fish, from which 92 were diagnosed with mycobacteriosis by histopathology, culture or both. Microscopic lesions variably consisted of random foci of coagulative necrosis in multiple organs, containing high numbers of free bacteria and large aggregates or sheets of macrophages with cytoplasm laden with acid-fast bacilli. Mycobacterial associated granulomas were identified in only six seahorses. Five fish had positive cultures with no observed microscopic changes. RNA-seq of the head kidney was performed to investigate the transcriptome of two infected and six non-infected lined seahorses Hippocampus erectus. Assembled and annotated putative transcripts serve to enrich the database for this species, as well as provide baseline data for understanding the pathogenesis of mycobacteriosis in seahorses. Putative components of the innate immune system (IL-1β, IL-6, TNF, NOS, Toll-like receptor 1, MHC Class I, NF-κβ, transforming growth factor beta, MyD88) were identified in the RNA-seq data set. However, a homolog for a key component in the TH1 adaptive immune response, interferon-gamma, was not identified and may underlie the unique pathologic presentation.
海龙科（海马、叶形海龙和管口鱼）因非结核分枝杆菌而遭受重大损失。然而，与其他硬骨鱼物种相比，它们对这种疾病产生的病变明显不同，尤其是肉芽肿形成很少见。本研究评估了270条海龙科鱼类，其中92条通过组织病理学、培养或两者确诊患有分枝杆菌病。显微镜下的病变各不相同，包括多个器官中随机出现的凝固性坏死灶，含有大量游离细菌以及大量聚集或成片的巨噬细胞，其细胞质中充满抗酸杆菌。仅在6只海马中发现了与分枝杆菌相关的肉芽肿。5条鱼培养结果呈阳性，但未观察到显微镜下的变化。对头肾进行了RNA测序，以研究两条感染和六条未感染的直立海马（Hippocampus erectus）的转录组。组装并注释的推定转录本有助于丰富该物种的数据库，同时为了解海马分枝杆菌病的发病机制提供基线数据。在RNA测序数据集中鉴定出了先天免疫系统的推定成分（IL-1β、IL-6、TNF、NOS、Toll样受体1、MHC I类、NF-κβ、转化生长因子β、MyD88）。然而，未鉴定出TH1适应性免疫反应关键成分干扰素-γ的同源物，这可能是其独特病理表现的基础。
