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1.
Viral haemorrhagic septicaemia (VHS), caused by the novirhabdovirus viral haemorrhagic septicaemia virus (VHSV), causes significant economic problems to European rainbow trout, Oncorhynchus mykiss (Walbaum), production. The virus isolates can be divided into four distinct genotypes with additional subgroups. The main source of outbreaks in European rainbow trout farming is sublineage Ia isolates. Recently, this group of isolates has been further subdivided in to two subclades of which the Ia‐2 consists of isolates occurring mainly in Continental Europe outside of Denmark. In this study, we sequenced the full‐length G‐gene sequences of 24 VHSV isolates that caused VHS outbreaks in Polish trout farms between 2005 and 2009. All these isolates were identified as genotype Ia‐2; they divided however into two genetically distinct subgroups, that we name Pol I and Pol II. The Pol I isolates mainly caused outbreaks in the southern part of Poland, while Pol II isolates predominantly were sampled in the north of Poland, although it seems that they have been transmitted to other parts of the country. Molecular epidemiology was used for characterization of transmission pathways. This study shows that a main cause of virus transmission appears to be movement of fish. At least in Polish circumstances trading practices appear to have significant impact on spreading of VHSV infection. 相似文献
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Melena J Bayot B Betancourt I Amano Y Panchana F Alday V Calderón J Stern S Roch P Bonami JR 《Journal of fish diseases》2006,29(10):589-600
Larvae and post-larvae of Penaeus vannamei (Boone) were submitted to primary challenge with infectious hypodermal and haematopoietic necrosis virus (IHHNV) or formalin-inactivated white spot syndrome virus (WSSV). Survival rate and viral load were evaluated after secondary per os challenge with WSSV at post-larval stage 45 (PL45). Only shrimp treated with inactivated WSSV at PL35 or with IHHNV infection at nauplius 5, zoea 1 and PL22 were alive (4.7% and 4%, respectively) at 10 days post-infection (p.i.). Moreover, at 9 days p.i. there was 100% mortality in all remaining treatments, while there was 94% mortality in shrimp treated with inactivated WSSV at PL35 and 95% mortality in shrimp previously treated with IHHNV at N5, Z1 and PL22. Based on viral genome copy quantification by real-time PCR, surviving shrimp previously challenged with IHHNV at PL22 contained the lowest load of WSSV (0-1x10(3) copies microg-1 of DNA). In addition, surviving shrimp previously exposed to inactivated WSSV at PL35 also contained few WSSV (0-2x10(3) copies microg-1 of DNA). Consequently, pre-exposure to either IHHNV or inactivated WSSV resulted in slower WSSV replication and delayed mortality. This evidence suggests a protective role of IHHNV as an interfering virus, while protection obtained by inactivated WSSV might result from non-specific antiviral immune response. 相似文献
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神经坏死病毒(nervous necrosis virus,NNV)是一种世界范围内流行、严重危害多种海水和淡水鱼类的传染性病原。NNV为单一正链、2节段RNA病毒,基因组由RNA1(3.1 kb)和RNA2(1.4 kb)组成。在病毒复制过程中,会合成亚基因组RNA3。RNA1编码RNA聚合酶。RNA2编码衣壳蛋白,为病毒的唯一结构蛋白。RNA3编码B1和B2两种非结构蛋白。根据病毒衣壳蛋白的基因序列,神经坏死病毒可以分成4种基因型,分别为拟鲹、红鳍东方鲀、条斑星鲽和赤点石斑神经坏死病毒基因型。但是,目前只发现A、B、C三种病毒血清型,A对应拟鲹神经坏死病毒基因型,B对应红鳍东方鲀神经坏死病毒基因型、C对应条斑星鲽神经坏死病毒和赤点石斑神经坏死病毒基因型。病毒存在垂直和水平两种传播途径,而且广泛分布于养殖和野生鱼类中。阻断病毒在野生与养殖鱼类之间的传播和开展新型鱼类疫苗研发是将来研究趋势。 相似文献
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Betanodavirus infections of teleost fish: a review 总被引：20，自引：0，他引：20
In the last decade betanodavirus infections have emerged as major constraints on the culture of marine fish in all parts of the world with the exception of the African continent. The occurrence of these infections appears to be a function of the number of species cultured and the intensity of culture. This has been further complicated by the promiscuous translocation of stock within and between countries. Great strides have been made in defining these agents and producing diagnostic techniques but much more remains to be done. Lack of knowledge of the epidemiology of the diseases caused by nodaviruses, except for vertical transmission of the pathogen in some species, has impeded the development of control measures but, even so, the measures identified to date have not been adequately implemented by producers with the result that catastrophic losses still occur on a regular basis. 相似文献
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Viral haemorrhagic septicaemia (VHS) is a serious disease in several fish species. VHS is caused by the rhabdovirus viral haemorrhagic septicaemia virus (VHSV). To prevent spreading of the pathogen, it is important to use a fast, robust, sensitive and specific diagnostic tool to identify the infected fish. Traditional diagnosis based on isolation in cell culture followed by identification using, for example, ELISA is sensitive and specific but slow. By switching to RT‐PCR for surveillance and diagnosis of VHS the time needed before a correct diagnosis can be given will be considerably shortened and the need for maintaining expensive cell culture facilities reduced. Here we present the validation, according to OIE guidelines, of a sensitive and specific Taqman‐based real‐time RT‐PCR. The assay detects all isolates in a panel of 79 VHSV isolates covering all known genotypes and subtypes, with amplification efficiencies of approximately 100%. The analytical and diagnostic specificity of the real‐time RT‐PCR is close to 1, and the analytical and diagnostic sensitivity is comparable with traditional cell‐based methods. In conclusion, the presented real‐time RT‐PCR assay has the necessary qualities to be used as a VHSV surveillance tool on par with cell culture assays. 相似文献
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Protective immunity of sevenband grouper, Epinephelus septemfasciatus Thunberg, against experimental viral nervous necrosis 总被引：9，自引：0，他引：9
This paper describes the protective immune responses of sevenband grouper, Epinephelus septemfasciatus Thunberg, immunized with live piscine nodavirus, the causative agent of viral nervous necrosis (VNN), or the Escherichia coli – expressed recombinant coat protein. Nodavirus-neutralizing antibodies were detected at titres ranging from 1:158 to 1:1257 in serum of sevenband grouper which survived intramuscular injection with the virus, by a cell culture assay system. The virus-neutralizing ability of immune serum was also confirmed by injecting virus previously treated with serum into fish. This indicates establishment of acquired immunity in survivors and thus explains why survivors from natural infection are resistant to recurrence of the disease. Young sevenband grouper were immunized twice by intramuscular injections with the recombinant coat protein. Immunized fish produced neutralizing antibodies at high titres for at least 110 days and showed significantly lower mortalities in virus challenge tests. These results suggest the potential for vaccination against VNN in sevenband grouper, which is susceptible to piscine nodavirus at all life-stages. 相似文献
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Susceptibility of cultured juveniles of several marine fish to the sevenband grouper nervous necrosis virus 总被引：4，自引：0，他引：4
Piscine nodaviruses (betanodaviruses) have been tentatively divided into four genotypes (SJNNV, RGNNV, TPNNV and BFNNV) and it is suggested that host specificity is different among these genotypes. In the present study, a betanodavirus [sevenband grouper nervous necrosis virus (SGNNV)] belonging to the redspotted grouper nervous necrosis virus (RGNNV) genotype, to which most betanodaviruses from warm water fish are identified, was evaluated for its pathogenicity to hatchery-reared juveniles of several marine fish species. When challenged with the virus by a bath method (10(5.1) TCID50 mL(-1)), sevenband grouper, Epinephelus septemfasciatus, Japanese flounder, Paralichthys olivaceus, and tiger puffer, Takifugu rubripes, displayed behavioural abnormalities and mortalities with distinct histopathological signs of viral nervous necrosis and heavily immunostained cells were observed in the central nervous tissues and retina. Bath-challenged rock fish, Sebastiscus marmoratus, and a hybrid of sevenband grouper and kelp grouper, E. moara, did not display any behavioural abnormality or mortality during the experimental period, although many fish showed slight signs of viral infection in nerve cells. Kelp grouper and red sea bream, Pagrus major, showed no behavioural abnormality, mortality or immunohistopathological changes after the virus challenge. These results are, in part, consistent with the natural host range of RGNNV, indicating the complexity in the host specificity of betanodaviruses. 相似文献
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R Pakingking Jr R Seron L dela Peña K Mori H Yamashita T Nakai 《Journal of fish diseases》2009,32(5):457-463
Asian sea bass, Lates calcarifer (Bloch), exhibited strong immune responses against a single injection of the formalin-inactivated red-spotted grouper nervous necrosis virus (RGNNV), a betanodavirus originally isolated in Japan. Fish produced neutralizing antibodies at high titre levels from days 10 (mean titre 1:480) to 116 (1:1280), with the highest titre at day 60 post-vaccination (1:4480). When fish were challenged with the homologous RGNNV at day 54 post-vaccination, there were no mortalities in both the vaccinated and unvaccinated control fish. However, a rapid clearance of the virus was observed in the brains and kidneys of vaccinated fish, followed by a significant increase in neutralizing-antibody titres. Furthermore, the vaccine-induced antibodies potently neutralized Philippine betanodavirus isolates (RGNNV) in a cross-neutralization assay. The present results indicate the potential of the formalin-inactivated RGNNV vaccine against viral nervous necrosis (VNN) of Asian seabass. 相似文献
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Procedures for a viral replication in excised fin tissue (VREFT) assay were adapted to Pacific herring, Clupea pallasii, and optimized both to reduce processing time and to provide the greatest resolution between naïve herring and those previously exposed to viral haemorrhagic septicaemia virus (VHSV), Genogroup IVa. The optimized procedures included removal of the left pectoral fin from a euthanized fish, inoculation of the fin with >105 plaque‐forming units (PFU) mL?1 VHSV for 1 h, rinsing the fin in fresh medium six times to remove unadsorbed virions, incubation of the fin in fresh medium for 4 days and enumeration of the viral titre in a sample of the incubation medium by plaque assay. The optimized VREFT assay was effective at identifying the prior exposure history of laboratory‐reared Pacific herring to VHSV. The geometric mean VREFT value was significantly greater (P < 0.01) among naïve herring (1.2 × 103 PFU mL?1) than among groups that survived exposure to VHSV (1.0–2.9 × 102 PFU mL?1); additionally, the proportion of cultures with no detectable virus was significantly greater (P = 0.0002) among fish that survived exposure to VHSV (39–47%) than among naïve fish (3.3%). The optimized VREFT assay demonstrates promise for identifying VHSV exposure history and forecasting disease potential in populations of wild Pacific herring. 相似文献
12.
红螯螯虾感染白斑综合征病毒 总被引：2，自引：1，他引：2
红螯螯虾(Cherax quadricarinatus)是澳州淡水龙虾的一种,属甲壳纲、十足目、长尾亚目、拟螯虾科、光壳虾属,原产地澳大利亚,具有个体大、生长快、食性杂、易饲养等养殖性能优势;同时,因其肉味鲜美、富含低胆固醇蛋白质,是目前世界上较名贵的淡水经济虾之一。目前,美国、拉丁美 相似文献
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鱼类诺达病毒及其所导致的疾病 总被引：1，自引：1，他引：1
In recent years, piscine nodaviruses have emerged as major pathogens of a wide range of larval and juvenile marine finfish resulting in high mortality in aquaculture worldwide. Affected fish exhibit a range of neurological signs, such as erratic swimming behaviour with the associated microscopic lesions of necrosis and vacuolation of the central nervous tissues and retina. Numerous roundshaped, unenveloped and 25-30 nm in diameter virus particles were found in the cytoplasm of affected retinal and nerve cells. Nodaviruses have a bipartite genome of positivesense RNA,with RNA1 encoding the RNAdependent RNA polymerase and RNA2 encoding the capsid protein. Both RNA are capped, but not polyadenylated. The family Nodaviridae comprises two genera: Alphanodavirus and Betanodavirus, members of which primarily infect insects and fish, respectively. Therefore, betanodavirus is also named piscine nodavirus. At present, piscine nodaviruses are divided into four genotypes based on partial sequences of the coat protein gene. ELISA and RT-PCR amplification have been developed as specific diagnostic methods for the d
etection of the virus. Antibodies to striped jack (Pseudocaranx dentex) nervous necrosis (SJNNV) were found in 65% of plasma samples collected from wild and domestic brood stocks of striped jack, suggesting that the virus is
very prevalent. Viral antigens were detected in eggs, larvae, and ovaries of hatcheryreared and wild spawner fish, suggesting both horizontal and vertical modes of transmission of the virus. Selection of nodavirusfree spawners using ELISA for detection of antigens and RT-PCR techniques have successfully reduced incidences of the virus infections in juvenile sea bass (Dicentrarchus labrax),striped jack and barfin flounder (Verasper moseri). The SSN1 and GF cell lines have been successfully used in isolating piscinenodaviruses.Although there are many papers describing the molecular characteristics of betanodavirus, our knowledge of the genomic attributes of these viruses is still limited. Vaccination studies are being undertaken by a number of researchers and need to be fostered. In particular, the use of passive immunization of broodfish with homologous and heterologous, high titre antisera are worthy of investigation. 相似文献
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2000~2002年,应用光镜和电子显微技术对AVND发生期间栉孔扇贝(Chlamys farreri)各主要组织器官病理变化进行了连续观察。光镜观察显示,除生殖腺、闭壳肌外,濒死栉孔扇贝的外套膜、鳃、肾、消化腺和肠组织都有不同程度的组织病理变化。病灶主要出现在上述各器官的结缔组织以及上皮组织,病理变化表现为细胞核肿大、固缩、破裂,核染色质边缘化或空泡化,受感染细胞崩解、脱落,留下大片均质无结构的空白区域,形成凝固性坏死,结缔组织细胞质中有嗜碱性包涵体样颗粒存在。电镜观察显示,在病灶出现的组织细胞内,细胞核染色质异常凝集和边缘化、核膜周隙扩张或溶解。细胞器病理变化明显,内质网扩张,核糖体脱落,有髓鞘样小体出现;线粒体肿大、嵴融解,整个细胞出现解体现象。病变的结缔组织细胞与间质细胞细胞质中有大量直径为130~170nm、具有囊膜的球形病毒粒子存在,负染电镜观察表明,病毒囊膜表面覆有长20nm放射状纤突。病毒的发生基质在细胞质内,并被一膜性结构所包围。病毒在宿主细胞中的繁殖分为3个阶段,即病毒发生期、病毒装配期和病毒释放期。病理学观察证明,病毒感染与病理变化具有明显的相关性。 相似文献
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为制备病毒性出血性败血症病毒(VHSV)单链抗体(single chain variable fragment antibody,ScFv)并鉴定其生物学功能,本研究提取抗VHSV单抗1G5的杂交瘤细胞株总RNA并反转录获得cDNA模板,通过PCR扩增VHSV抗体的轻链可变区(VL)和重链可变区(VH)编码序列,将其拼接成单链抗体Sc Fv基因后插入载体pET28a中,构建原核表达重组质粒并在大肠杆菌中诱导表达。结果表明,单链抗体主要以可溶性形式表达,分子量约28 ku,能特异性识别VHSV病毒的G蛋白并对VHSV病毒具有体外中和活性,其对VHSV病毒的G蛋白亲和力(KD)达到1.4×10~(–8) M。单链抗体ScFv的制备为进一步研究VHSV的治疗性抗体、快速诊断试剂奠定了基础。 相似文献
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S P Jonstrup T Gray S Kahns H F Skall M Snow N J Olesen 《Journal of fish diseases》2009,32(11):925-929
A database has been created, http://www.FishPathogens.eu , with the aim of providing a single repository for collating important information on significant pathogens of aquaculture, relevant to their control and management. This database will be developed, maintained and managed as part of the European Community Reference Laboratory for Fish Diseases function. This concept has been initially developed for viral haemorrhagic septicaemia virus and will be extended in future to include information on other significant aquaculture pathogens. Information included for each isolate comprises sequence, geographical origin, host origin and useful key literature. Various search mechanisms make it easy to find specific groups of isolates. Search results can be presented in several different ways including table-based, map-based and graph-based outputs. When retrieving sequences, the user is given freedom to obtain data from any selected part of the genome of interest. The output of the sequence search can be readily retrieved as a FASTA file ready to be imported into a sequence alignment tool of choice, facilitating further molecular epidemiological study. 相似文献
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A Gregory L A Munro M Snow K L Urquhart A G Murray R S Raynard 《Journal of fish diseases》2009,32(6):481-489
This study investigated infection dynamics of infectious salmon anaemia virus (ISAV) by conducting two experiments to examine minimum infective dose and viral shedding of ISAV. In terms of minimum infective dose, the high variability between replicate tanks and the relatively slow spread of infection through the population at 1 × 101 TCID50 mL−1 indicated this dose is approaching the minimum infective dose for ISAV in seawater salmon populations. A novel qPCR assay incorporating an influenza virus control standard with each seawater sample was developed that enabled the quantity of ISAV shed from infected populations to be estimated in values equivalent to viral titres. Viral shedding was first detected at 7 days post-challenge (5.8 × 10−2 TCID50 mL−1 kg−1 ) and rose to levels above the minimum infective dose (4.2 × 101 TCID50 mL−1 kg−1 ) on day 11 post-challenge, 2 days before mortalities in ISAV inoculated fish started. These results clearly demonstrate that a large viral shedding event occurs before death. Viral titres peaked at 7.0 × 101 TCID50 mL−1 kg−1 15 days post-infection. These data provide important information relevant to the management of ISA. 相似文献