Year of grant:
Náttúra og náttúrutilfeingi
Molecular epidemology of infectious salmon anaemia virus (ISAV) in Atlantic salmon aquaculture in Faroe Islands
Debes Hammershaimb Christiansen
Peter S. Østergaard, Knut Falk, Ole Bendik Dale, Iveta Matejusova, Alistair J.A. McBeath og Mickael Fourrier
Grant from the FRC in DKK:
Molecular epidemiology of infectious salmon anaemia virus (ISAV) in Atlantic salmon aquaculture in Faroe Islands
The aim of the present project is to characterize the genome of Faroese ISAV variants and to link this information to ISAV epidemiology to get a better understanding on virulence markers, the risk of low-pathogenic ISAV evolving into a virulent ISAV strain and transmission pathways. This knowledge is highly demanded by the authorities and the Atlantic salmon farming industry.
Atlantic salmon farming is an increasingly important source of food and income worldwide. However, the emergence of infectious diseases constantly threatens farmed fish welfare and farmers’ economy, and may also impact wild fish populations. Atlantic salmon aquaculture is one of the most important industries in the Faroe Islands. The industry has grown rapidly from the beginning in the 1970s to a production of more than 50.000 tons in 2010. From 2000 to 2005 the ISAV caused an ISA epidemic which resulted in an almost total collapse of the aquaculture industry. Lack of national management strategy played a major role in the devastating consequences of the ISA epidemic. A prerequisite for implementing such optimal strategy is knowledge on virus characteristics and local virus epidemiology. This knowledge is however limited in the Faroes and, consequently, the management strategy is mainly based on knowledge Atlantic salmon farming countries.
During a five year study period following the Faroese ISA epidemic we have shown that a low-pathogenic variant of ISAV, designated ISAV-HPR0 is highly prevalent and causes a non-clinical and transient infection of mainly the gills of farmed Atlantic salmon (Christiansen et al., J Gen Virol 2011;92:909-918). Genetic analysis showed a close association between ISAV-HPR0 and ISAV responsible for the ISA outbreaks in the Faroes, in line with the hypothesis that new pathogenic ISAV variants have arisen in aquaculture through known and unknown genetic changes in ISAV-HPR0.
We here suggest the use of molecular virological methods for structural and epidemiological characterization of ISAV.
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