Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA.
Kennebec River Biosciences, Richmond, ME, USA.
J Vet Diagn Invest. 2024 May;36(3):346-356. doi: 10.1177/10406387231209035. Epub 2023 Nov 2.
Members of the genus are emergent pathogens of cultured eels, as well as several characid and cyprinid species. Since 2013, has been reported from diseased barramundi () cultured in North America; we recovered 8 isolates from diseased fish during different outbreaks from the same farm. The isolates from barramundi were compared phenotypically and genetically to isolates characterized from ornamental fish and recovered from aquatic and terrestrial animals. All barramundi isolates were PCR-positive for the surface protective antigen type B () gene, and shared ≥ 99.7% sequence similarity among concatenated multilocus sequence analysis gene sequences, indicating a high degree of genetic homogeneity. These isolates were > 99% similar to other positive isolates from marine invertebrates and marine mammals, consistent with findings for other types. The and isolates shared < 98% similarity, as well as < 90% similarity with positive . Similar clonality among the isolates was observed using repetitive element palindromic PCR. In experimental intracoelomic injection challenges conducted to fulfill Koch postulates, 67% of exposed tiger barbs () died within 14 d of challenge. Our study supports previous work citing the genetic variability of spp. types and the emergence of members of the genus as nascent fish pathogens.
属的成员是养殖鳗鱼以及几种脂鲤科和鲤科鱼类的新兴病原体。自 2013 年以来，已从北美养殖的患病巨牙鱼（）中报告了属；我们从同一养殖场的不同暴发中从患病鱼类中分离出了 8 株。从患病巨牙鱼中分离出的与从观赏鱼中分离出的属，并从水生和陆生动物中分离出的属在表型和遗传上进行了比较。所有巨牙鱼分离株的表面保护抗原 B（）基因 PCR 均为阳性，并且在连接的多位点序列分析基因序列中共享≥99.7%的序列相似性，表明遗传同源性很高。这些分离株与来自海洋无脊椎动物和海洋哺乳动物的其他阳性分离株的相似性>99%，与其他 类型一致。与其他阳性分离株相比，和 分离株的相似性<98%，与阳性 的相似性<90%。使用重复元件回文 PCR 观察到属分离株之间的克隆性相似。在为满足科赫假设而进行的实验性腹腔内注射挑战中，暴露的老虎鲈（）中有 67%在挑战后 14 天内死亡。我们的研究支持先前的工作，即引用了属的遗传变异性和属成员作为新生鱼类病原体的出现。
