Outbreaks of Koi Herpesvirus Disease in Rivers of Kanagawa Prefecture

Hara, Hideo; Aikawa, Hideaki; Usui, Kazushige; Nakanishi, Teruyuki

doi:10.3147/jsfp.41.81

Cited by 13 publications

(9 citation statements)

References 6 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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“…Experimentally, KHVD has been reproduced in temperatures ranging from 16 to 28°C (Gilad et al, 2003(Gilad et al, , 2004Yuasa, Ito, & Sano, 2008) and the lowest temperature associated with a CyHV-3 outbreak was 15.5°C in a field survey in Japan (Hara, Aikawa, Usui, & Nakanishi, 2006). Interestingly, CyHV-2 induces mortalities in goldfish at a slightly enlarged temperature range from 15 to 30°C (Ito & Maeno, 2014) suggesting a similar but adaptable temperature range in cyprinid herpesviruses.…”

Section: Effect Of Water Temperaturementioning

confidence: 87%

Cyprinid Herpesvirus 3

Boutier

Ronsmans

Rakus

et al. 2015

Advances in Virus Research

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“…Comparable observations have been made for herpesviruses infecting vertebrates: for example, temperatures between 18°C and 28°C have been shown to favor the onset and the severity of Koi herpesvirus infection in fish (Gilad et al 2003;Hara et al 2006;Pokorova et al 2005;Saint-Hilaire et al 2005;Sano et al 2004;Yuasa et al 2008). However, it remains difficult to define a precise temperature threshold leading to enhanced OsHV-1 expression or mortality.…”

Section: Virus Diversitymentioning

confidence: 99%

Mass mortality in bivalves and the intricate case of the Pacific oyster, Crassostrea gigas

Solomieu

Renault

Travers

2015

Journal of Invertebrate Pathology

151

100

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Massive mortality outbreaks in cultured bivalves have been reported worldwide and they have been associated with infection by a range of viral and bacterial pathogens. Due to their economic and social impact, these episodes constitute a particularly sensitive issue in Pacific oyster (Crassostrea gigas) production. Since 2008, mortality outbreaks affecting C. gigas have increased in terms of intensity and geographic distribution. Epidemiologic surveys have lead to the incrimination of pathogens, specifically OsHV-1 and bacteria of the Vibrio genus, in particular Vibrio aestuarianus. Pathogen diversity may partially account for the variability in the outcome of infections. Host factors (age, reproductive status...) including their genetic background that has an impact on host susceptibility toward infection, also play a role herein. Finally, environmental factors have significant effects on the pathogens themselves, on the host and on the host-pathogen interaction. Further knowledge on pathogen diversity, classification, and spread, may contribute toward a better understanding of this issue and potential ways to mitigate the impact of these outbreaks.

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Outbreaks of Koi Herpesvirus Disease in Rivers of Kanagawa Prefecture

Cited by 13 publications

References 6 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

Cyprinid Herpesvirus 3

Mass mortality in bivalves and the intricate case of the Pacific oyster, Crassostrea gigas

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