A review of infectious gill disease in marine salmonid fish

Infectious gill diseases of marine salmonid fish present a significant challenge in salmon-farming regions. Infectious syndromes or disease conditions affecting marine-farmed salmonids include amoebic gill disease (AGD), proliferative gill inflammation (PGI) and tenacibaculosis. Pathogens involved include parasites, such as Neoparamoeba perurans, bacteria, such as Piscichlamydia salmonis and Tenacibaculum maritimum, and viruses, such as the Atlantic salmon paramyxovirus (ASPV). The present level of understanding of these is reviewed with regard to risk factors, potential impacting factors, methods of best practice to mitigate infectious gill disease, as well as knowledge gaps and avenues for future research.     

铁岭市主要养殖区鱼病调查与分析

2007年5月至2009年9月,通过对铁岭市辖区的开原市、铁岭县、昌图县淡水鱼类主要养殖区的池塘和小型水库鱼类常见鱼病种类、发病季节、流行情况及危害程度进行调查与分析,初步摸清了近三年鱼病的种类、流行、发病特点.共发现鱼病12种:其中细菌性鱼病6种、寄生虫病5种、真菌类鱼病1种,其中细菌性鱼病和寄生虫性鱼病是主要水产养...     

菱湖鱼病工作站: 现代科学改造中国传统养鱼业的序曲

寄生虫是水产养殖中最主要的病原类群之一,对鱼类苗种直至成鱼各个阶段的危害都十分严重。我国的鱼病学即是从鱼类寄生虫的研究发端并逐步发展起来的。本文从病原生物学、生态学、药物学、免疫学四个方面回顾了我国淡水鱼类寄生虫自新中国建立初期至今70年间 (1953年—2023年)的研究历程和已取得的成绩,并对未来的发展趋势和前沿热点进行了展望。本文为从事鱼类寄生虫学以及水产其他相关研究的读者提供了关于中国鱼类寄生虫研究的历史、现在发展水平和未来发展动向等较为全面的素材。

     

有害赤潮藻对鱼类影响的研究进展

赤潮灾害的多发性和普遍性极大危害了海产养殖业和渔业资源,严重破坏了正常的海洋生态系统,直接威胁着人类的生存环境和健康水平[1,2]。在赤潮灾害中,鱼类的大量死亡带来的危害和损失占相当大的比重[3],在我国,1998年春季南海的一次特大赤潮造成了大规模的养殖鱼死亡,直接经济损失超过3亿元。在这类赤潮灾害中不仅渔业资源和鱼类养殖业遭受了极大的破坏,海洋生物的种群结构乃至整个海洋生态系统也受到了影响,毒素在鱼类体内的累积威胁着食用者的生命安全[4]。因此,科学家们针对有害赤潮藻及其毒素对鱼类的影响开展了一些调查和研究工作…     

鱼类和水生动物基因组作图研究的现状及前景

鱼类和水生动物基因组作图（ｇｅｎｏｍｅ ｍａｐｐｉｎｇ）研究落后于陆生动物。水生经济动物的遗传图谱只是最近二、三年才有报道［１－３］。虽然起步晚，但以鱼类为代表的水生动物的基因组研究已经有了可观进展。本文试图从如下几个方面作一综述：１．分子遗传标记及其在基因组作图研究中的应用，２．水生动物基因组研究的现状，３．水生动物基因组作图的前景。１ 分子遗传标记及其在基因组作图研究中的应用１．１ 分子遗传标记 遗传标记一般可分为形态学标记、细胞学标记、生化标记和ＤＮＡ分子标记。其中只有ＤＮＡ分子标记是核苷酸水…     

Effect of fish density and number of infectious fish on the survival of rainbow trout fry, Oncorhynchus mykiss (Walbaum), during epidemics of infectious pancreatic necrosis

Two laboratory studies compared the effect of fish density and number of infectious fish on characteristics of survival of rainbow trout fry during controlled epidemics of infectious pancreatic necrosis (IPN). Analyses of hazard functions and survivor functions were used to determine whether peak death rate, time at which the peak death rate occurred and probability of survival to the end of the experiment were associated with fish density and number of infectious fish added (i.e. pathogen concentration). When number of infectious fish was low and fish density increased, the peak death rate increased, time of the peak death rate decreased and the probability of survival to the end of the experiment decreased. When number of infectious fish was high, the effect of density diminished. Loglogistic regression of survival data revealed that fish density, number of infectious fish and interaction between these two variables significantly affected time to death from IPN (P < 0.01).     

Current knowledge of nocardiosis in teleost fish

Nocardia sp. is the causative agent of nocardiosis, a lethal granulomatous disease of the skin, muscle, and various inner tissues affecting various teleost and shellfish. Four species of Nocardia have been isolated from diseased fish and shellfish, namely Nocardia asteroides, Nocardia seriolae, Nocardia salmonicida and Nocardia crassostreae. Therefore, in fish aquaculture, nocardiosis has caused severe economic losses, especially in the Asian region. Considerable research has been performed, since the first report of identified Nocardia sp. in fish, to characterize Nocardia sp. and identify rapid detection techniques, immune response against infection and prophylactic approaches. In this review, the current state of knowledge about nocardiosis in fish has been presented, including the pathogenesis, diagnosis, host immune response and vaccine development.     

Characterization of spaC‐type Erysipelothrix sp. isolates causing systemic disease in ornamental fish

Since 2012, low‐to‐moderate mortality associated with an Erysipelothrix sp. bacterium has been reported in ornamental fish. Histological findings have included facial cellulitis, necrotizing dermatitis and myositis, and disseminated coelomitis with abundant intralesional Gram‐positive bacterial colonies. Sixteen Erysipelothrix sp. isolates identified phenotypically as E. rhusiopathiae were recovered from diseased cyprinid and characid fish. Similar clinical and histological changes were also observed in zebrafish, Danio rerio, challenged by intracoelomic injection. The Erysipelothrix sp. isolates from ornamental fish were compared phenotypically and genetically to E. rhusiopathiae and E. tonsillarum isolates recovered from aquatic and terrestrial animals from multiple facilities. Results demonstrated that isolates from diseased fish were largely clonal and divergent from E. rhusiopathiae and E. tonsillarum isolates from normal fish skin, marine mammals and terrestrial animals. All ornamental fish isolates were PCR positive for spaC, with marked genetic divergence (<92% similarity at gyrB, <60% similarity by rep‐PCR) between the ornamental fish isolates and other Erysipelothrix spp. isolates. This study supports previous work citing the genetic variability of Erysipelothrix spp. spa types and suggests isolates from diseased ornamental fish may represent a genetically distinct species.     

Antiviral activity of casein and αs2 casein hydrolysates against the infectious haematopoietic necrosis virus,a rhabdovirus from salmonid fish

Salmonid fish viruses, such as infectious haematopoietic necrosis virus (IHNV), are responsible for serious losses in the rainbow trout and salmon‐farming industries, and they have been the subject of intense research in the field of aquaculture. Thus, the aim of this work is to study the antiviral effect of milk‐derived proteins as bovine caseins or casein‐derived peptides at different stages during the course of IHNV infection. The results indicate that the 3‐h fraction of casein and α_S2‐casein hydrolysates reduced the yield of infectious IHNV in a dose‐dependent manner and impaired the production of IHNV‐specific antigens. Hydrolysates of total casein and α_S2‐casein target the initial and later stages of viral infection, as demonstrated by the reduction in the infective titre observed throughout multiple stages and cycles. In vivo, more than 50% protection was observed in the casein‐treated fish, and the kidney sections exhibited none of the histopathological characteristics of IHNV infection. The active fractions from casein were identified, as well as one of the individual IHNV‐inhibiting peptides. Further studies will be required to determine which other peptides possess this activity. These findings provide a basis for future investigations on the efficacy of these compounds in treating other viral diseases in farmed fish and to elucidate the underlying molecular mechanisms of action. However, the present results provide convincing evidence in support of a role for several milk casein fractions as suitable candidates to prevent and treat some fish viral infections.     

Detection and molecular characterization of infectious spleen and kidney necrosis virus from major ornamental fish breeding states in Peninsular Malaysia

‘Gold standard’ OIE reference PCR assay was utilized to detect the presence of infectious spleen and kidney necrosis virus (ISKNV) in freshwater ornamental fish from Malaysia. From total of 210 ornamental fish samples representing 14 species, ISKNV was detected in 36 samples representing 5 fish species. All positive cases did not show any clinical signs of ISKNV. Three restriction enzymes analyses showed that the fish were infected by identical strains of the same virus species within Megalocytivirus genus. Major capsid protein (MCP) genes of 10 ISKNV strains were sequenced and compared with 9 other reference nucleotide sequences acquired from GenBank. Sequence analysis of MCP gene showed that all strains detected in this study were closely related to the reference ISKNV with nucleotide sequence identity that was ranging from 99.8% to 100%. In addition, phylogenetic analysis of MCP gene revealed that viruses from genus Megalocytivirus can be divided into three genotypes: genotype 1 include reference ISKNV and all other strains that were detected in this study, genotype 2 include viruses closely related to red sea bream iridovirus (RSIV), and genotype 3 include viruses closely related turbot reddish body iridovirus (TRBIV).     

Phenotypical and genotypical characterization of Shewanella putrefaciens strains isolated from diseased freshwater fish

Between 2007 and 2012, a variety of disease outbreaks most often characterized by skin disorders were observed among different species of freshwater fish in Poland. In most cases, the clinical signs included focally necrotized gills, necrotic skin lesions or ulcers. Internally, haemorrhages, oedematous kidney and abnormal spleen enlargement were generally noted. The disorders were accompanied by increased mortality. Most of the problems concerned cultured common carp Cyprinus carpio L. and rainbow trout Oncorhynchus mykiss (Walbaum). Fish have been examined from a number of these farms, and additionally, the wild and ornamental fish with similar clinical signs of diseases were also tested. Bacteria were isolated consistently from lesions and internal organs. They had characteristic orange-pigmented colonies which grew in pure culture or constituted 55–95% of total bacterial flora. One hundred and eighteen isolates were collected and biochemically identified as Shewanella putrefaciens group, and this was confirmed by sequencing. Challenge tests confirmed the pathogenicity of these bacteria. This is the first report characterizing and describing S. putrefaciens as a pathogen of different species of freshwater fish in Europe.     

中国淡水鱼类寄生虫研究七十年

寄生虫是水产养殖中最主要的病原类群之一,对鱼类苗种直至成鱼各个阶段的危害都十分严重。我国的鱼病学即是从鱼类寄生虫的研究发端并逐步发展起来的。本文从病原生物学、生态学、药物学、免疫学四个方面回顾了我国淡水鱼类寄生虫自新中国建立初期至今70年间(1953年—2023年)的研究历程和已取得的成绩,并对未来的发展趋势和前沿热点进行了展望。本文为从事鱼类寄生虫学以及水产其他相关研究的读者提供了关于中国鱼类寄生虫研究的历史、现在发展水平和未来发展动向等较为全面的素材。     

鱼类免疫增强剂的研究现状与进展

现代水产养殖业追求优质高产,但在大规模高密度的养殖生产中,往往会导致鱼体的抗应激能力下降,病害增多,成活率下降,造成重大经济损失。近年来,国内外学者对鱼类免疫机制及其病害防治方法已进行了大量研究,其中免疫增强剂因能增强机体抗疾病感染的能力,其免疫增强作用所需时间较短,且没有记忆成分,被认为是一种提高鱼体免疫活性及疾病抵抗力的有效方法,具有重要的应用价值。     

细菌性鱼病快速诊断技术的进展

简要地归纳了当前国内外学者应用现代生物技术检测细菌性鱼病的手段，主要有：荧光抗体技术、免疫酶技术、单克隆抗体技术、核酸杂交技术、聚合酶链反应（ＰＣＲ）技术、以及电子计算机应用技术等，反映了鱼病学实用诊断技术的进展情况     

Distribution of infectious pancreatic necrosis virus (IPNV) in wild marine fish from Scottish waters with respect to clinically infected aquaculture sites producing Atlantic salmon, Salmo salar L

This study represents the first large-scale investigation of IPNV in Scottish wild marine fish. Kidney samples were taken from 30 627 fish comprising 37 species and 45 isolations were made from nine different species, illustrating these as reservoirs of IPNV in Scottish waters. The estimated prevalence of IPNV in the Scottish marine environment was low at 0.15% (90% confidence intervals, (CI) of 0.11-0.19%). This was significantly greater in fish caught less than 5.0 km from IPN-positive fish farms in Shetland, at 0.58% (90% CI of 0.45-0.77%). This prevalence persisted and did not significantly decrease over the 16-month period of study. The estimated prevalence of IPNV for each positive species was less than 1% with the statistically non-significant exceptions of flounder, Platichthys flesus (L.), at 12.5% (90% CI of 0.64-47.06%) and saithe, Pollachius virens (L.), at 1.11% (90% CI of 0.49-2.19%). The 45 isolates were titrated and all but two were below the detection limit of the test (<55 PFU g(-1)). Titres of 3.8 x 10(2) PFU g(-1) and 2.8 x 10(1) PFU g(-1) were calculated from common dab, Limanda limanda (L.), and saithe, respectively. This study provides evidence that clinical outbreaks of IPN in farmed Atlantic salmon may cause a localized small increase in the prevalence of IPNV in wild marine fish.     

鱼类生态形态学研究进展

生态形态学(ecological morphology or ecomorphology)是一门比较的学科,是生物学和生态学的交叉领域.自从Karr和James[1]介绍"生态形态学"一词以来,对这个领域的研究兴趣稳步增长.在20世纪80年代以前,强调研究大量生态和形态变量之间的广泛联系,或者研究与Hutchinson生态位理论相一致的形态和生态格局.     

鱼类疱疹病毒研究进展概述

疱疹病毒是双链DNA病毒家族成员之一,具有高度的传染性,严重危及人类及动物的健康;其中异疱疹病毒科各成员是引起水生动物病害的主要病原,严重制约全球水产养殖业的健康发展,尤其对我国鱼类养殖产业影响巨大.本文简要概述鱼类疱疹病毒研究发展历程、现状及进展,主要包括鲤疱疹病毒、(鮰)疱疹病毒、鲑疱疹病毒及其他鱼类疱疹病毒等,以...