Epidemiological investigation of infectious salmon anaemia (ISA) outbreaks in Norway 2003–2005

Lyngstad, Trude Marie; Jansen, P. A.; Sindre, Hilde; Jonassen, Christine Monceyron; Hjortaas, M J; Johnsen, Soeren Paaske; Brun, Edgar

doi:10.1016/j.prevetmed.2007.12.008

Cited by 67 publications

(74 citation statements)

References 16 publications

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“…The re-emergence of ISAV in Chile is responsible for one of the largest epidemics, surpassed only between 1989 and 1991, when 215 farms reported ISA outbreaks in Norway (Lyngstad et al 2008). As in previous ISA epidemics, cases were clustered around the IC, which supports the hypothesis that passive transmission in seawater through normal discharge from ISAVinfected farms (proximity) is the most important risk factor in the spread of the disease, as suggested elsewhere (Vågsholm et al 1994, Jarp & Karlsen 1997, Gustafson et al 2005, McClure et al 2005.…”

Section: Discussionsupporting

confidence: 73%

“…ISAV was first isolated in Norway in 1984 (Thorud & Djupvik 1988). Subsequently, ISAV has spread throughout Norway and remains endemic along most of the country's shoreline (Lyngstad et al 2008). The first ISA outbreak affecting farmed salmon outside Norway was reported in 1996 in New Brunswick, Canada, however, ISAV infection in this industry had been suspected since 1994 (Mullins et al 1998, Lovely et al 1999) and the last virulent strain of ISAV was detected in this area by active surveillance in June 2007 (M. Beattie pers.…”

Section: Introductionmentioning

confidence: 99%

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Epidemiologic investigation of the re-emergence of infectious salmon anemia virus in Chile

Mardones¹,

Pérez²,

Carpenter³

2009

Dis. Aquat. Org.

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Reports from surveillance activities were analyzed to determine the epidemiology of the re-emergence of infectious salmon anemia virus (ISAV) in Atlantic salmon farms in Chile. The epidemic and spatial and spatiotemporal patterns were described, taking into account commercial compartmentalization of the farms. During the 64 wk study period, 76 ISAV-infected salmon farms, representing 17 companies, were reported in 65% of the management geographic zones of the 10th region in southern Chile. Approximately 20% of the farms at risk became infected, with the incidence rate increasing slightly over time. Results from epidemic analyses and observed spatial and spatiotemporal patterns suggested an initial dispersal and subsequent clustering of cases around the index case (IC) in a propagated epidemic mode. Results suggested that delayed depopulation may have been a key factor in the spread and persistence of ISAV. Clustering of cases supported the assumption that passive transmission in seawater from ISAV-infected farms (proximity) is a critical factor in controlling disease. The re-emergence of ISAV in Chile has resulted in one of the largest ISAV epidemics reported in the world and this study generates new hypotheses and provides useful information for spatial disease control planning in salmon farming areas.

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Section: Discussionsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Epidemiologic investigation of the re-emergence of infectious salmon anemia virus in Chile

Mardones¹,

Pérez²,

Carpenter³

2009

Dis. Aquat. Org.

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“…Jarp & Karlsen (1997) identified an enhanced risk of infection (odds ratio 8) if infected farms were within 5 km of the farm assessed, the odds increasing as the distance decreased. Scheel et al (2007) and Lyngstad et al (2008) have also identified proximity as a risk factor.These modes of transport are effective over different distances and result in a variety of patterns of spread. In the present study, the significance of different forms of spread is assessed in the light of the outbreak pattern and data on contact distributions implied by these different routes.…”

mentioning

confidence: 99%

“…These plants were also visited by FHIs to assess biosecurity and disinfection regimes as a failure of these could have the potential to contaminate the surrounding waters and hence, potentially, visiting vessels. Vertical transmission: There is disagreement as to whether ISAV is vertically transmitted (Lyngstad et al 2008, Vike et al 2009). If vertical transmission did occur then this could be significant both as a potential source of the Shetland outbreak, since imported ova are used (although these are certified ISAV-free), and as a potential route of spread within Scotland and beyond via Shetland-reared broodstock.…”

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confidence: 99%

Epidemiological investigation into the re-emergence and control of an outbreak of infectious salmon anaemia in the Shetland Islands, Scotland

Murray¹,

Munro²,

Wallace³

et al. 2010

Dis. Aquat. Org.

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Infectious salmon anaemia (ISA) is an orthomyxoviral disease, primarily affecting marine-phase farmed Atlantic salmon, which can result in high levels of mortality. ISA first emerged in Norway in the 1980s and subsequently has occurred in Canada, the USA, the Faeroe Islands and Chile. An outbreak occurred in Scotland in 1998-1999, but was eradicated at a cost of over £20M. The epidemiology of a new outbreak of ISA in the Scottish Shetland Islands during 2008-2009 is described. Six sites have been confirmed ISA-positive. Spread of the virus via transport of fish between marine sites, harvest vessels, smolts and wild fish appears to have been of little or no importance, with spread primarily associated with marine water currents. The use of management areas by Marine Scotland to control the event appears to have been effective in restricting spread to a small area. This localised outbreak contrasts with the 1998-1999 outbreak that spread over a wide geographic area with transported fish and harvest vessels. The development and application of industry codes of good practice, good husbandry and biosecurity practices, limited marine site-to-site movement of live fish and improved disinfection of vessels and processing plant waste that occurred subsequent to the 1998-1999 outbreak may explain the localised spread of infection in [2008][2009]. Depopulation of confirmed sites has been achieved within 7 wk (mean = 3.7 wk); however, it is likely that subclinical infection persisted undetected for months on at least 1 site. The origin of the 2008-2009 outbreak remains unknown. Potential sources include evolution from a local reservoir of infection or importation. Synchronous fallowing of management areas, with good husbandry and biosecurity, reduces the risk of ISA recurring. Movement of fish between sites in different management areas represents the greatest risk of regional-scale spread, should this occur.KEY WORDS: Infectious salmon anaemia · ISA · Epidemiology · Control · Eradication · Hydrodynamics · Harvest · Scotland Resale or republication not permitted without written consent of the publisherDis Aquat Org 91: [189][190][191][192][193][194][195][196][197][198][199][200] 2010 behind ISA spread and how current Scottish fish farming structures and practices led to the spatial limitation of such spread, thus creating the conditions under which ISA could be controlled and eradicated.In 2008, Scotland produced 128 606 metric tonnes (t) of farmed Atlantic salmon from 257 marine sites and 2628 t of sea-farmed rainbow trout Oncorhynchus mykiss from 9 sites (Walker 2009). A further 311 t of brown and sea trout (both Salmo trutta) were also produced, but separate statistics are not published for marine and freshwater farms. (Both O. mykiss and S. trutta can carry the virus but do not develop clinical ISA [OIE 2009]). A third of Scottish salmon production (42 593 t) came from the Shetland Islands.Scottish salmon production is divided for the purposes of disease control into management areas (MAs) (Marine Scotland ...

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“…Además, la proximidad de sitios con brotes del virus ISA es un factor de riesgo significativo en el cultivo de salmones en Noruega (Jarp & Karlsen, 1997;Murray et al, 2002;Gustafson et al, 2005;McClure et al, 2005;Sheel et al, 2007). Lyngstad et al (2008) sugieren que la propagación contigua de los sitios infectados es consistente con la transmisión horizontal de la enfermedad, pero no está claro, si esto se debe al contacto entre sitios con brotes, transmisión pasiva vía agua de mar o algún otro factor local, ya que no se ha encontrado un reservorio definido del virus.…”

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Caligus rogercresseyi: posible vector en la transmision horizontal del virus de la anemia infecciosa del salmon (ISAv)

Oelckers¹,

Vike²,

Duesund³

et al. 2015

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RESUMEN.Chile el año 2007 se convirtió en el segundo país productor de salmónidos a nivel mundial. Al año siguiente la industria salmonera nacional comenzó a experimentar una severa crisis sanitaria producida por el virus causante de la anemia infecciosa del salmón. Este virus se presentó por primera vez en Noruega (1984), luego en Canadá, Escocia, Islas Faroe, Estados Unidos y Chile (2007). La anemia infecciosa del salmón (ISA), es una enfermedad altamente contagiosa entre los peces, producida por un virus de la familia Orthomyxoviridae. La especie más vulnerable a este virus es el salmón del Atlántico (Salmo salar). La plaga parasitaria producida por el piojo de mar, Caligus rogercresseyi, copépodo ectoparásito, ha ido en aumento lo que favorece el contagio de enfermedades bacterianas y virales. De todas las especies cultivadas en Chile, el salmón del Atlántico, S. salar) es una de las especies más susceptibles de ser infestadas por C. rogercresseyi. Durante el 2006, la industria presentó un aumento significativo en las tasas de infestación por Caligus; luego en el 2007, aparecieron brotes del virus ISA. En Noruega, se ha demostrado que el piojo de mar, Lepeophtherius salmonis puede tener un rol como vector en la transmisión del virus ISA, por lo que el objetivo de este trabajo fue determinar si C. rogercresseyi es un vector de transmisión del virus ISA en el salmón del Atlántico, cultivado en el sur de Chile. Palabras clave: Caligus rogercresseyi, copépodo ectoparásito, vector, anemia infecciosa del salmón, ISA.

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Epidemiological investigation of infectious salmon anaemia (ISA) outbreaks in Norway 2003–2005

Cited by 67 publications

References 16 publications

Epidemiologic investigation of the re-emergence of infectious salmon anemia virus in Chile

Epidemiologic investigation of the re-emergence of infectious salmon anemia virus in Chile

Epidemiological investigation into the re-emergence and control of an outbreak of infectious salmon anaemia in the Shetland Islands, Scotland

Caligus rogercresseyi: posible vector en la transmision horizontal del virus de la anemia infecciosa del salmon (ISAv)

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