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1.
Fish samples initially collected by local veterinarians on the common and koi carp farms in Poland between 2013 and 2015 as part of a KHV surveillance programme, when the water temperature was between 16 and 26 °C, and were also tested for CEV by qPCR. A partial 478 nucleotide fragment of the 4a gene was subsequently generated from 17 qPCR‐positive common carp Cyprinus carpio samples from 36 farm sites tested during the period. Sequence alignments and analysis revealed the presence of CEV in Poland both in common carp as well as in koi carp farms, and phylogenetic analysis assigned the Polish CEV sequences into three distinct genogroups. A lineage which includes the original sequences obtained from koi carp in Japan (genogroup II) included sequences from both koi carp and common carp, and the second lineage (genogroup I) contained sequences from common carp only. A third lineage (genogroup III) which was more closely related to the genogroup II also consisted of sequences from common carp only. The latter represents a lineage of CEV not previously described in the literature.  相似文献   

2.
Hungary is an important carp producer with intensive trading relationships with farms in other carp‐producing areas in Europe. Carp in Europe were recently found infected with carp edema virus (CEV), a poxvirus which causes the koi sleepy disease (KSD) syndrome. Moribund carp were collected from 17 fish farms and angling ponds in different regions of Hungary. Histological analysis of gills from these carp revealed a proliferation of the interlamellar epithelium and an infiltration by eosinophilic cells. In 13 of 17 of these carp, CEV DNA was detected by qPCR and in seven fish more than 1 × 104 copies of virus‐specific DNA sequences per 250 ng of DNA, which could be considered as clinically relevant and a cause of disease. A phylogenetic analysis of the sequences revealed that all three genogroups of CEV were present in Hungarian common carp with genogroup I being most abundant. These results support the hypothesis of a prolonged presence of CEV in European carp populations and suggest that previous outbreaks of KSD were not recorded or misdiagnosed. Hence, a testing of carp and koi for infection with CEV should be included into disease surveillance programmes to prevent further spreading of this disease.  相似文献   

3.
Koi herpesvirus (KHV; cyprinid herpesvirus‐3) and carp oedema virus (CEV) are important viruses of common and koi carp (Cyprinus carpio); however, the distribution of these viruses in wild common carp in North America is largely unknown. During the summers of 2017 and 2018, 27 mass mortalities of common carp were reported from four states in the USA (Minnesota, Iowa, Pennsylvania and Wisconsin), the majority of which were distributed across eight major watersheds in southern Minnesota. Samples from 22 of these mortality events and from five clinically healthy nearby carp populations were screened for KHV, CEV and SVCV using real‐time polymerase chain reaction (qPCR). KHV was confirmed in 13 mortality events, CEV in two mortality events and coinfections of KHV/CEV in four mortality events. Nucleotide sequence analysis revealed that the KHV and CEV detected here are closely related to European lineages of these viruses. While molecular detection alone cannot conclusively link either virus with disease, the cases described here expand the known range of two important viruses. This is also the first reported detection of KHV and CEV coinfections in wild carp populations.  相似文献   

4.
鲤浮肿病(carp edema virus disease,CEVD)是在锦鲤中发现的一种传染性病毒病,近年来在全球传播迅速,对鲤养殖业造成严重损害。本研究设计CEV环介导等温扩增(loop-mediated isothermal amplification,LAMP)引物,进行特异性实验;选取套式PCR、荧光PCR和LAMP三种检测方法,组织10家实验室进行室间比对测试:制备含CEV病毒核酸的测试样品,评价其均匀性和稳定性,通过测试结果分析方法检出限。结果显示,套式PCR的核酸样品检测限可达6.8×10-10 g。  相似文献   

5.
Carp oedema virus (CEV) and koi herpes virus (KHV) are of major concern to common carp breeders and koi enthusiasts worldwide. The viruses cause diseases that exhibit similar external signs; thus, it is difficult to distinguish between them clinically. In this study, we developed and optimized rapid and accurate single‐ and multiplex isothermal diagnostic tools, based on recombinase polymerase amplification (RPA), for detection and differentiation of CEV and KHV. The assays were combined with a lateral flow dipstick to enable visual detection of amplification products and simplify post‐amplification analysis. Both CEV‐ and KHV‐RPA assays were specific for their target virus. The lower detection limits of the assays were similar to those of established diagnostic PCR tests for the viruses. A sample preparation method was optimized to eliminate the need for total DNA extraction from fish tissues. The estimated time to perform these RPA assays, from receiving the sample to having a result, is 50 min, compared to 10 and 7 hr for CEV‐ and KHV‐PCR tests, respectively. The assays can be performed in field situations to improve screening of fish and reduce spread of these viruses and thereby enhance the common carp and koi industries.  相似文献   

6.
Common carp (Cyprinus carpio) is a very important fish species for warm-water aquaculture in Croatia. All Croatian carp farms are subjected to a surveillance programme for the presence of koi herpesvirus (KHV), causing a deadly disease called koi herpesvirus disease (KHVD). However, there is no surveillance for other viral pathogens of importance like carp edema virus (CEV), a causative agent of koi sleepy disease (KSD). During regular testing within the KHVD surveillance programme, we tested samples for CEV simultaneously. The screening indicated possible outbreaks of KHVD and KSD. During 2016, KHVD broke out in an isolated area and soon thereafter a KHV eradication programme was successfully performed. However, during 2018 and 2019, two additional mortality events occurred in lakes in the southern part of Croatia during the spring. Samples from both events tested positive for CEV. An epidemiological investigation confirmed the introduction of infected carps from an infected farm to one of the lakes. To prevent the spreading of CEV into open waters, it is of utmost importance to introduce CEV testing before fish movement or to perform regular testing of all carp farms in the country to determine CEV prevalence for the purpose of implementation of control measures.  相似文献   

7.
During a PCR‐based CEV survey in Poland in 2015–2017, the virus was detected in many farms both in clinical and asymptomatic cases and in common as well as in koi carp (Cyprinus carpio). In order to evaluate the potential carrier role of fish species that share the same habitats with carp, an experimental trial was performed. Investigations carried out on specimens of bleak (Alburnus alburnus), crucian carp (Carassius carassius), European perch (Perca fluviatilis), Prussian carp (Carassius gibelio), roach (Rutilus rutilus) and tench (Tinca tinca) cohabited with CEV‐infected carp yielded positive results. These species of fish were experimentally cohabited with CEV‐infected common carp at a temperature of 16°C ± 1. Material from the brain, gills, spleen, kidneys, intestine and skin was investigated for the presence of CEV DNA. Similar investigations were performed with uninfected fish designated controls. Samples were tested for CEV by qPCR.  相似文献   

8.
Koi herpesvirus (KHV) causes KHV disease (KHVD). The virus is highly contagious in carp or koi and can induce a high mortality. Latency and, in some cases, a lack of signs presents a challenge for virus detection. Appropriate immunological detection methods for anti‐KHV antibodies have not yet been fully validated for KHV. Therefore, it was developed and validated an enzyme‐linked immunosorbent assay (ELISA) to detect KHV antibodies. The assay was optimized with respect to plates, buffers, antigens and assay conditions. It demonstrated high diagnostic and analytical sensitivity and specificity and was particularly useful at the pond or farm levels. Considering the scale of the carp and koi industry worldwide, this assay represents an important practical tool for the indirect detection of KHV, also in the absence of clinical signs.  相似文献   

9.
草鱼呼肠孤病毒湖州分离株的分离及鉴定   总被引：2，自引：0，他引：2       下载免费PDF全文
2008年6月从湖州某患病草鱼池塘采集草鱼出血病疑似病样,将除菌过滤后的患病鱼肝、脾、肾组织滤液,注射健康的8～10 cm的草鱼鱼种.5d后草鱼开始发病,且症状与原发病症状一样,死亡率为57%,对照组未有死亡.将无菌处理的病样滤液接种草鱼肾细胞(CIK),连续接5代均出现明显的细胞病变(CPE),并与草鱼呼肠孤病毒参考株所产生的CPE一致.该株病毒的TCID50为10-8/0.1ml.内脏组织经超薄切片,电子显微镜观察,发现组织内有大量的病毒颗粒,大小均一,近似球形,直径约70～75 nm.理化鉴定表明,氯仿、乙醚处理组病毒的感染力和对照组相比并没有多大变化,说明该株病毒对氯仿和乙醚有一定的抗性.经草鱼呼肠孤病毒特异性的RT-PCR检测,获得阳性的目的片段,测序的结果与草鱼呼肠孤病毒相应序列的同源性达99%以上.上述鉴定结果表明所分离的病毒为草鱼呼肠孤病毒,将其命名为HZ2008.  相似文献   

10.
The koi herpesvirus (KHV) has spread worldwide since its discovery in 1998 and causes disease and mortality in koi and common carp populations with a high impact on the carp production industry. Many investigations have been conducted to examine ways of distribution and to identify possible transmission vectors. The answers, however, raise many new questions. In the present study, different wild fish species taken from carp ponds with a history of KHV infection were examined for their susceptibility to the virus. In the tissue of these fish, the virus load was determined and it was tested whether a release of the virus could be induced by stress and the virus then could be transferred to naive carp. Wild fish were gathered from carp ponds during acute outbreaks of virus‐induced mortality in summer and from ponds stocked with carp carrying a latent KHV infection. From these ponds, wild fish were collected during the harvesting process in autumn or spring when the ponds were drained. We found that regardless of season, temperature variation, age and infection status of the carp stock, wild fish from carp ponds and its outlets could be tested positive for the KHV genome using real‐time PCR with a low prevalence and virus load. Furthermore, virus transfer to naive carp was observed after a period of cohabitation. Cyprinid and non‐cyprinid wild fish can therefore be considered as an epidemiological risk for pond carp farms.  相似文献   

11.
为研究鲤浮肿病毒的感染方式及在锦鲤各组织器官中的动态分布,在水温20～22℃,溶解氧7～8mg/L试验条件下,采用注射、浸泡、划伤后浸泡3种方式人工感染锦鲤,观察了试验鱼的发病和死亡情况;检测了鲤浮肿病毒在感染鱼体内各组织器官中的存在情况,探讨了主要被感染组织的病理变化。试验结果显示,采用注射、浸泡、划伤后浸泡3种方式均可导致健康锦鲤感染该病毒,病鱼出现昏睡、烂鳃、凹眼等症状,累积死亡率35%～88%。锦鲤感染该病毒后至少有3d的潜伏期,随后病毒在鳃组织中大量增殖,至7d达到高峰,病毒量314.8个/ng,之后病毒量开始逐渐下降,至12d在鳃组织中检测不出病毒。鲤浮肿病毒在肾、肝、脑、肌肉和脾中存在的时间较短且病毒量较低,在血液和肠道中未检出。结合鳃组织病理切片可知,鳃为该病毒感染的主要靶器官。本研究结果为鲤浮肿病的诊断和防控提供了一定的科学依据。  相似文献   

12.
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13.
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14.
Cyprinid herpesvirus 3 (CyHV-3), which causes a lethal disease in common carp, Cyprinus carpio L., and koi, C. carpio koi , first occurred in Lake Biwa, Japan in 2004. To elucidate distribution of CyHV-3 in a wild common carp population, we conducted a PCR survey of CyHV-3 among such fish in Lake Biwa in 2006. Only 6% (1/18) of the common carp smaller than 300 mm were positive with PCR, whereas 31% (18/58) of fish larger than 300 mm were positive. To evaluate their past exposure to CyHV-3 infection based on the presence of antibodies, we also measured the levels of serum anti-CyHV-3 antibodies in the carp, using an enzyme-linked immunosorbent assay. None (0/26) of the fish smaller than 300 mm was positive for the antibodies, whereas 54% (33/61) of fish larger than 300 mm were positive. Of the antibody-positive individuals, 44% (14/32) were also positive by PCR strongly suggesting that wild common carp that survived infection become CyHV-3 carriers. Five individuals were positive by PCR but negative for antibodies indicating that their infection with CyHV-3 had occurred recently. These results suggest that transmission of CyHV-3 from carriers to naïve common carp is still occurring in Lake Biwa.  相似文献   

15.
Koi herpesvirus (KHV) poses a significant threat to cultured koi and common carp, both Cyprinus carpio L. Since the first reported case in Israel in 1998, KHV has rapidly spread worldwide. This study investigates the spread of KHV to Taiwan by collecting 49 cases of suspected common carp and koi infections from 2003 to 2005 for analysis. Clinical signs included lethargy, anorexia, increased respiratory movements and uncoordinated swimming. Hyperaemia, haemorrhage on body surface and necrotic gill filaments were recorded. Gill epithelial hyperplasia, necrosis and eosinophilic intranuclear inclusion bodies were observed by histological examination, while virions were detected using transmission electron microscopy. By detecting the presence of the KHV thymidine kinase (TK) gene and the KHV 9/5 gene using polymerase chain reaction (PCR), 37 cases were identified as KHV-positive, and the cumulative mortality of infected fish was 70-100%. Positive cases showed identical sequences for the genes analysed, implying that they were of the same origin. For the KHV 9/5 gene sequence, these cases exhibited 100% identity with the Japanese strain (TUMST1, accession number AP008984) and 99% identity with the Israeli (KHV-I, DQ177346) and US (KHV-U, DQ657948) strains. Additionally, a loop-mediated isothermal amplification (LAMP) assay was performed and found to be more sensitive than PCR tests, suggesting its potential use as a rapid diagnostic method for KHV. This is the first epidemiological study of KHV infection in cultured common carp and koi in Taiwan.  相似文献   

16.
Cyprinid herpesvirus 3 (CyHV‐3) or koi herpesvirus (KHV) is a virulent viral infection in common carp and koi. The disease has caused global epizootic and economic loss in fish aquaculture and in the wild. Clinacanthus nutans (Burm. f.) Lindau is a well‐known medicinal plant used in Thai traditional medicine. Virucidal effects of the plant extract against human herpes simplex virus have been reported. In this study, C. nutans crude extract was tested for antiviral activities against CyHV‐3 in koi carp. Results showed effective antiviral activity against CyHV‐3 pre‐ and post‐infection. The 50% lethal concentration (LC50) of extract was higher than 5 mg/ml. The 50% effective dose (ED50) was 0.99 mg/ml, 0.78 mg/ml, 0.75 mg/ml and 0.71 mg/ml at 1, 2, 3 and 4 hr pre‐infection, respectively. The ED50 from post‐infection tests was 2.05 mg/ml and 2.34 mg/ml at 0 and 24 hr, respectively. These results demonstrated that crude extract expressed antiviral activity against CyHV‐3 and can be applied as a therapeutic agent in common carp and koi aquaculture.  相似文献   

17.
Infectious haematopoietic necrosis virus (IHNV) and spring viraemia of carp virus (SVCV) are both rhabdoviruses of fish, listed as notifiable disease agents by the World Organization for Animal Health. Recombinant rhabdoviruses with heterologous gene substitutions have been engineered to study genetic determinants and assess the potential of these recombinant viruses for vaccine development. A recombinant IHNV (rIHNV), containing the full‐length genome of a European IHNV strain, was modified by deleting the glycoprotein (G) gene and replacing it with a European SVCV G‐gene to make the rIHNV‐Gsvcv. The chimeric rIHNV‐Gsvcv level of virulence in rainbow trout, common carp and koi was assessed, and its ability to induce a protective immune response in surviving koi against wild‐type SVCV infection was tested. The rIHNV‐Gsvcv infection of trout led to high mortality, ranging from 78% to 92.5%, after immersion. In contrast, no deaths occurred in juvenile common carp after infection with rIHNV‐Gsvcv by either immersion or intraperitoneal (IP) injection. Similarly, koi infected with rIHNV‐Gsvcv via IP injection had little to no mortality (≤9%). Koi that survived initial infection with a high dose of recombinant virus rIHNV‐Gsvcv were protected against a virulent SVCV challenge resulting in a high relative per cent survival of 82.5%.  相似文献   

18.
Abstract  Koi carp is an ornamental variant of the common carp, Cyprinus carpio L., that was introduced to New Zealand in the 1960s and has since become a major aquatic pest. A total of 1265 wild adult koi carp were caught by boat electric fishing, dart tagged and released at multiple sites in the lower Waikato River and associated lakes and wetlands between September 2002 and February 2005. Subsequent recaptures by boat electric fishing and recreational fishing returned 76 koi carp (6% of all tagged fish). Of these, 85% were recaptured less than 5 km from their release site; only one fish moved more than 50 km. On seven occasions, pairs or small groups of koi carp (20% of all tag returns) that had previously been tagged and released at the same locations and times were subsequently recaptured together after considerable periods of time at liberty (mean 551 days ± 419 SD). Adult koi carp in the Waikato River showed a high degree of site fidelity, exhibited prolonged social groupings and females moved downstream more often than males.  相似文献   

19.
Performance tests of Northern mirror carp (M72) and three different crossbreds were conducted in semi‐intensive pond conditions from the larval stage up to market size. The aim of this study was to evaluate the possible utilization of new hybrid combinations (M72 × PL – Poho?elice mirror carp) and (M72 × Dor – Israeli mirror carp), and to compare them with a hybrid widely reared as a commercial product (M72 × M2 – Hungarian mirror carp) and with M72 purebred. The testing model was derived from similar studies carried out in the conditions of the Czech Republic, where an internal control of different scale cover is used to eliminate all non‐genetic effects. ancova revealed at market size significantly better growth in M72 × Dor (1 619±28.3 g; LS mean±SE) and M72 × PL (1475±29.8 g) compared with M72 (1278±26.3 g). Survival during the test of 3 years duration was significantly the best in the M72 × Dor hybrid as were the dressing out parameters measured at market size, even if these were significantly different only in proportion of fillets with skin (39.1±0.28%). Interestingly, the crossbred M72 × M2 commonly used by Czech fishermen showed for both, growth (1371±26.2 g) and survival, the lowest values among crossbreds and with regard to dressing out parameters mostly among all tested groups.  相似文献   

20.
Since virus isolation is seldom successful, KHV infection is commonly detected by PCR examination. A number of different PCR assays have been described in recent years. However, at present no commonly accepted PCR method is used amongst different laboratories. The aim of this study was to check if the examination of infected fish by different PCR methods yielded comparable results. We used tissue samples of three KHV‐infected koi, one KHV‐infected common carp, one KHV‐infected goldfish and one non‐infected common carp. DNA was extracted with DNAzol Reagent, High Pure PCR Template DNA Preparation Kit and QIAamp DNA Mini Kit. The DNA was tested by PCR with different combinations of published primer sets –KHV‐F and ‐R, KHV‐Gray‐2F and ‐2R and KHV‐TKf and ‐TKr – plus different DNA polymerases – a standard Taq DNA polymerase, a Platinum (hotstart) Taq DNA polymerase and a Platinum (hotstart) Pfx DNA polymerase with proofreading activity. The different extraction methods produced DNA solutions with different yields of DNA and different degrees of homogeneity. Also, the sensitivity of the PCR depended on the choice of the primer set and polymerase. Not all infected fish could be identified with all methods; there were large differences in the sensitivity between methods.  相似文献   

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