Epidemiological Description of A New Viral Disease Afflicting Cultured Cyprinus Carpio In Israel (original) (raw)
Related papers
Epidemiological description of a new viral disease afflicting cultured Cyprinus carpio in
2003
Since spring 1998, a new disease causing high mortality has afflicted cultured ornamental and common carps (Cyprinus carpio) in Israel. The clinical signs of the disease are fatigue, gasping movements in shallow water, gill necrosis, sunken eyes, pale patches on the skin and increased mucus secretion. The disease was experimentally transmitted to koi and common carp of various ages by injection with affected tissue filtrates, cohabitation trials and exposure to the isolated viral agent. Immersion of healthy fish in tanks containing 2.7 x 10 4 plaque forming units (PFU) per l or intraperitoneal injection (0.2 ml) of a viral inoculum of 1000 PFU/ml were sufficient to induce the terminal disease in over 80% of the fish. Here we report that the disease is restricted to C. carpio, that young fish of 2.5 g and 6 g are more sensitive to the virus than adults (230 g) and that the virus remains active in the water for at least four hours.
Description of an as Yet Unclassified DNA Virus from Diseased Cyprinus carpio Species
Journal of Virology, 2005
Numerous deaths of koi and common carp (Cyprinus carpio) were observed on many farms throughout Israel, resulting in severe financial losses. The lethal viral disease observed is highly contagious and extremely virulent, but morbidity and mortality are restricted to koi and common carp populations. Diseased fish exhibit fatigue and gasping movements in shallow water. Infected fish had interstitial nephritis and gill necrosis as well as petechial hemorrhages in the liver and other symptoms that were not consistent with viral disease, suggesting a secondary infection. Here we report the isolation of carp nephritis and gill necrosis virus (CNGV), which is the etiologic agent of this disease. The virus propagates and induces severe cytopathic effects by 5 days postinfection in fresh koi or carp fin cell cultures (KFC and CFC, respectively), but not in epithelioma papillosum cyprini cells. The virus harvested from KFC cultures induced the same clinical signs, with a mortality of 75 to 95%, upon inoculation into naive koi and common carp. Using PCR, we provide final proof that the isolated virus is indeed the etiologic agent of food and ornamental carp mortalities in fish husbandry. Electron microscopy revealed viral cores with icosahedral morphology of 100 to 110 nm that resembled herpesviruses. Electron micrographs of purified pelleted CNGV sections, together with viral sensitivities to ether and Triton X-100, suggested that it is an enveloped virus. However, the genome of the isolated virus is a double-stranded DNA (dsDNA) molecule of 270 to 290 kbp, which is larger than known herpesviruses. The viral DNA seems highly divergent and bears only small fragments (16 to 45 bp) that are similar to the genomes of several DNA viruses. Nevertheless, amino acid sequences encoded by CNGV DNA fragments bear similarities primarily to members of the Poxviridae and Herpesviridae and to other large dsDNA viruses. We suggest, therefore, that the etiologic agent of this disease may represent an as yet unclassified virus species that is endemic in C. carpio (carp).
Efficient vaccine against the virus causing a lethal disease in cultured Cyprinus carpio
Vaccine, 2003
We have isolated a virus, which causes a mortal disease in cultured ornamental Koi and Common carps (Cyprinus carpio) in many countries worldwide. This unclassified virus, which causes nephritis and gill necrosis, and so has been given the name carp nephritis and gill necrosis virus (CNGV), has a morphology resembling the herpes virus, but bears a genomic DNA of ca 250-300 kbp. So far, both others and we have been unable to find CNGV-DNA sequences possessing a significant similarity to known DNA viruses. The virus induces a lethal disease when water temperature ranges between 18 and 25 • C (permissive temperature). In this report, we demonstrate that carps, exposed to the virus at 23 • C for 3-5 days and then transferred to the non-permissive temperature of 30 • C, became resistant to a challenged infection and their sera demonstrated a high level of virus-specific antibodies. We have isolated attenuated non-pathogenic viruses that render virus-vaccinated carps resistant to the disease. Furthermore, vaccinated fish developed high levels of antibodies against the virus. We suggest, therefore, that this attenuated virus could be used as a live vaccine for the eradication of the mortal disease afflicting Common and ornamental carp fisheries in many countries.
Journal of Fish Diseases
Spring viraemia of carp (SVC) is an infectious disease responsible for severe economic losses for various cyprinid species, particularly common carp (Cyprinus carpio carpio). The causative agent is the SVC virus (SVCV), a member of the Sprivivirus genus, Rhabdoviridae family, and a List 1 pathogen notifiable by the World Organization for Animal Health. This study describes the diagnosis of an SVCV pathogen isolated in October 2015 from wild common carp inhabiting a natural lagoon in central Mexico. While neither an epidemic nor fish mortalities were reported, the collected killed specimens exhibited clinical signs of disease (e.g., exopthalmia, moderate abdominal distension and haemorrhaging, as well as internal haemorrhages and adhesions). Histological results of injuries were consistent with the pathology caused by SVCV. This finding was supported by the isolation of a virus in EPC and BF-2 cells and subsequent RT-PCR confirmation of SVCV. The phylogenetic analyses of partial SVCV glycoprotein gene sequences classified the isolates into the Ia genogroup. These findings make this the first report of SVCV detection in Mexico, extending the southern geographical range of SVCV within North America. However, since this pathogen was detected in fish inhabiting a natural body of water without tributaries or effluents, it is difficult to estimate the risk of SVCV for other wild/feral cohabitating cyprinid species in the lagoon. The status of this virus is also unknown for other bodies of water within this region.
Diseases of Aquatic Organisms, 2017
Carp edema virus disease (CEVD), also known as koi sleepy disease, is caused by a poxvirus associated with outbreaks of clinical disease in koi and common carp Cyprinus carpio. Originally characterised in Japan in the 1970s, international trade in koi has led to the spread of CEV, although the first recognised outbreak of the disease outside of Japan was not reported until 1996 in the USA. In Europe, the disease was first recognised in 2009 and, as detection and diagnosis have improved, more EU member states have reported CEV associated with disease outbreaks. Although the structure of the CEV genome is not yet elucidated, molecular epidemiology studies have suggested distinct geographical populations of CEV infecting both koi and common carp. Detection and identification of cases of CEVD in common carp were unreliable using the original PCR primers. New primers for conventional and quantitative PCR (qPCR) have been designed that improve detection, and their sequences are provided in this paper. The qPCR primers have successfully detected CEV DNA in archive material from investigations of unexplained carp mortalities conducted >15 yr ago. Improvement in disease management and control is possible, and the principles of biosecurity, good health management and disease surveillance, applied to koi herpesvirus disease, can be equally applied to CEVD. However, further research studies are needed to fill the knowledge gaps in the disease pathogenesis and epidemiology that, currently, prevent an accurate assessment of the likely impact of CEVD on European koi and common carp aquaculture and on wild carp stocks.
Viruses of Fish: An Overview of Significant Pathogens
Viruses, 2011
The growing global demand for seafood together with the limited capacity of the wild-capture sector to meet this demand has seen the aquaculture industry continue to grow around the world. A vast array of aquatic animal species is farmed in high density in freshwater, brackish and marine systems where they are exposed to new environments and potentially new diseases. On-farm stresses may compromise their ability to combat infection, and farming practices facilitate rapid transmission of disease. Viral pathogens, whether they have been established for decades or whether they are newly emerging as disease threats, are particularly challenging since there are few, if any, efficacious treatments, and the development of effective viral vaccines for delivery in aquatic systems remains elusive. Here, we review a few of the more significant viral pathogens of finfish, including aquabirnaviruses and infectious hematopoietic necrosis virus which have been known since the first half of the 20th century, and more recent viral pathogens, for example betanodaviruses, that have emerged as aquaculture has undergone a dramatic expansion in the past few decades.
Aquaculture, 2005
Massive mortalities of edible and ornamental (koi) carp (Cyprinus carpio L.) have been encountered in several fish farms worldwide, including Israel. The disease-causing virus has been identified as koi herpes virus (KHV). Based on its pathogenic effect in fish, it has also been termed carp interstitial nephritis and gill necrosis virus (CNGV). The first objective of this work was to select virus-resistant fish by crossbreeding sensitive domesticated strains with resistant wild strains of carp. Frozen wild carp [Cyprinus carpio haematopterus; Sassan] sperm was brought from the Czech Republic to achieve heterosis by producing crossbreds. We compared growth rate, food consumption, survival and behavior among strains and crossbreds. Two strains of domesticated carp-Našice (N) and Dor-70 (D) and the wild Sassan (S) were used. A large quantity of Našice eggs were fertilized with semen of Našice, Dor-70 or Sassan to produce the NÂN, NÂD and NÂS crossbred groups, while a large quantity of Dor-70 eggs were fertilized with semen of Dor-70 or Sassan to produce the DÂD and DÂS groups. Resistance to the viral disease was evaluated by exposure to the virus in ponds and in the laboratory. The laboratory-exposure test was carried out at a water temperature of 22 to 23 8C and the fish were exposed to the disease by cohabitation. The DÂS crossbred was the most resistant (60.7% survival) and the NÂN crossbred most sensitive (8.0% survival); the other fish strains did not differ significantly from one another (NÂS-33.7%, DÂD-27.0%, and DÂN-17.7%). Similar tests, performed in ponds, were generally in good agreement with those from the laboratory, except for the NÂS crossbred, which showed good resistance in the ponds but only intermediate resistance in the laboratory. In the grow-out phase, the Sassan crossbreds exhibited equal (NÂS) or better (DÂS) growth rates as compared to the commercial crossbred (DÂN) and the pure strains (DÂD, NÂN). We used indirect immunofluorescence microscopy to evaluate the increasing amounts of virus in the sick fish. Kidneys were removed from naRve and sick fish and used for the preparation of touch imprint slides. The amount of viral protein produced by the 0044-8486/$ -see front matter D