Current knowledge on koi herpesvirus (KHV) - a review

Pokorová, Dagmar; Veselý, Tomáš; Piačková, Veronika; Reschova, S.; Hulova, J.

doi:10.17221/5607-vetmed

Cited by 98 publications

(64 citation statements)

References 18 publications

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“…High seawater temperatures appear to be one of the potential factors likely to induce OsHV-1 infection. This hypothesis is consistent with observations on koi herpesvirus, for which temperatures between 18°C and 28°C favored the onset and severity of disease in fish (35)(36)(37)(38)(39)(40). Field surveys conducted in Japan showed that the lowest water temperature at which outbreaks occurred was 15.5°C to 16°C (36,39).…”

Section: Discussionsupporting

confidence: 90%

Ostreid Herpesvirus 1 Infection among Pacific Oyster (Crassostrea gigas) Spat: Relevance of Water Temperature to Virus Replication and Circulation Prior to the Onset of Mortality

Renault

Bouquet²,

Maurice³

et al. 2014

Appl Environ Microbiol

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A number of bivalve species worldwide, including the Pacific oyster, Crassostrea gigas, have been affected by mass mortality events associated with herpesviruses, resulting in significant losses. A particular herpesvirus was purified from naturally infected larval Pacific oysters, and its genome was completely sequenced. This virus has been classified as Ostreid herpesvirus 1 (OsHV-1) within the family Malacoherpesviridae. Since 2008, mass mortality outbreaks among C. gigas in Europe have been related to the detection of a variant of OsHV-1 called Var. Additional data are necessary to better describe mortality events in relation to environmental-parameter fluctuations and OsHV-1 detection. For this purpose, a single batch of Pacific oyster spat was deployed in 4 different locations in the Marennes-Oleron area (France): an oyster pond ("claire"), a shellfish nursery, and two locations in the field. Mortality rates were recorded based on regular observation, and samples were collected to search for and quantify OsHV-1 DNA by real-time PCR. Although similar massive mortality rates were reported at the 4 sites, mortality was detected earlier in the pond and in the nursery than at both field sites. This difference may be related to earlier increases in water temperature. Mass mortality was observed among oysters a few days after increases in the number of PCR-positive oysters and viral-DNA amounts were recorded. An initial increment in the number of PCR-positive oysters was reported at both field sites during the survey in the absence of significant mortality. During this period, the water temperature was below 16°C. Since the first report by Farley et al. (1), herpesviruses have been associated worldwide with mortality events resulting in significant losses in a number of bivalve species, including the Pacific cupped oyster, Crassostrea gigas, in both hatcheries/nurseries and the natural environment (2-11). A herpesvirus was purified from naturally infected larval Pacific cupped oysters collected in 1995 in a French commercial hatchery (12). Its genome was completely sequenced (13), and the virus was classified as Ostreid herpesvirus 1 (OsHV-1) within the family Malacoherpesviridae (14, 15). Moreover, since 2008, mass mortality outbreaks among Pacific cupped oysters have been reported in Europe, including France, Ireland, the Channel Islands, and the United Kingdom (16-23), in relation to the detection of a particular genotype of OsHV-1 called Var (24).A protocol based on the intramuscular injection of 0.22-mfiltered tissue homogenates prepared from naturally infected spat was developed (25). The results of experimental trials showed that mortality was induced after the injection. Furthermore, analysis of injected oyster spat revealed large amounts of OsHV-1 DNA by real-time quantitative PCR. In this context, OsHV-1 was inferred to be the causative agent of the mortality reported in the study (25). In addition to transmitting OsHV-1 infection by intramuscular inoculation, waterborne transmission to healthy oyster sp...

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Section: Discussionsupporting

confidence: 90%

Ostreid Herpesvirus 1 Infection among Pacific Oyster (Crassostrea gigas) Spat: Relevance of Water Temperature to Virus Replication and Circulation Prior to the Onset of Mortality

Renault

Bouquet²,

Maurice³

et al. 2014

Appl Environ Microbiol

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“…The virus survives at low temperature but disease outbreaks occur at 17-28°C. No morbidities have been reported at 13 and 30°C [48]. The disease progression is very fast in summer and slow in winter [46].…”

Section: Koi Herpes Virusmentioning

confidence: 94%

“…After the first report of this disease in Israel, it has been reported in US and many other Asian and European countries [27,40,45,47,53,54]. This disease has been reported form Indonesia, Japan, Taiwan, Israel, Malaysia, Thailand, Singapore, Philippines, Hong Kong and Korea [1,48]. The infected fish show signs of erratic swimming behaviour, disorientation, gasping at the surface and high mortality.…”

Section: Koi Herpes Virusmentioning

confidence: 99%

Viruses of Freshwater Finfish in the Asian–Pacific Region

Sahoo

Goodwin

2012

Indian J. Virol.

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“…This disease was initially reported in 1998 in Israel and USA, where the outbreaks resulted in high mortality of koi and common carp (Cyprinus carpio) (Pokorova et al 2005).…”

mentioning

confidence: 99%

Susceptibility of stone loach (Barbatula barbatula) and hybrids between sterlet (Acipenser ruthenus) and beluga (Huso huso) to cyprinid herpesvirus 3

Pospichal¹,

Piačková²,

Pokorová³

et al. 2016

Vet. Med. - Czech

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Cyprinid herpesvirus 3 also known as koi herpesvirus is a causative agent of highly contagious disease (koi herpesvirus disease) and can cause significant losses in fish stocks. The disease is restricted to koi and common carp, but recent investigations have shown that other cyprinids as well as non-cyprinid species are asymptomatically susceptible to this virus and can play either a role as a potential carrier or can contribute to biological conservation of this virus. The susceptibility of two non-target species, stone loach (Barbatula barbatula) and sterbel -a hybrid between sterlet (Acipenser ruthenus) and beluga (Huso huso) to cyprinid herpesvirus 3 was tested by means of their co-habitation together with naïve koi and intraperitoneally KHV-infected koi (primary challenge). On the 15 th day post-infection (dpi), a secondary challenge was started (a portion of the surviving stone loach and sterbel were transferred to tanks with other naïve koi). All dead as well as surviving fish were investigated for the presence of KHV DNA in pooled samples of tissue from individual fish by nested PCR. Sampling for PCR from surviving fish was performed on the 15 th dpi and on the 30 th dpi of the primary challenge, and on the 30 th dpi of the secondary challenge. During the primary challenge (up to the 30 th dpi), average cumulative mortality in duplicated experimental groups was as follows: koi 100%, sterbel and stone loach both 5%. In the primary challenge, no surviving stone loach or sterbel sampled on the 15 th dpi or those that died previously were found to be positive for viral DNA. Results of PCR revealed the presence of KHV DNA in 95% of co-habited naïve koi samples. PCR analysis of tissues taken from surviving fish on the 30 th dpi revealed the presence of viral DNA in 77.8% (7/9) of stone loach and in 22.2% (2/9) of sterbel. Cumulative mortality of fish in the secondary challenge was 100% for stone loach and for koi co-habitating with them, and 50% for koi co-habitating with sterbel, which all survived. Despite the high mortality of koi and stone loach in the secondary challenge (probably caused by malfunction of biofilters or bacterial infection), none of them, nor any of the sturgeon hybrids were considered to be positive for KHV DNA. In summary, the hybrid between sterlet and beluga and the stone loach seemed to be susceptible to cyprinid herpesvirus 3, but we could not prove that they can transfer this virus to naïve koi.Keywords: CyHV-3; KHV; transmission; cohabitation List of abbreviationsCyHV-3 = cyprinid herpesvirus 3, CEFAS = Center for Environment, Fisheries and Aquaculture Science, dpi = days post infection, KHV = koi herpesvirus, PCR = polymerase chain reaction

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Current knowledge on koi herpesvirus (KHV) - a review

Cited by 98 publications

References 18 publications

Ostreid Herpesvirus 1 Infection among Pacific Oyster (Crassostrea gigas) Spat: Relevance of Water Temperature to Virus Replication and Circulation Prior to the Onset of Mortality

Ostreid Herpesvirus 1 Infection among Pacific Oyster (Crassostrea gigas) Spat: Relevance of Water Temperature to Virus Replication and Circulation Prior to the Onset of Mortality

Viruses of Freshwater Finfish in the Asian–Pacific Region

Susceptibility of stone loach (Barbatula barbatula) and hybrids between sterlet (Acipenser ruthenus) and beluga (Huso huso) to cyprinid herpesvirus 3

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