First detection, isolation and molecular characterization of infectious salmon anaemia virus associated with clinical disease in farmed Atlantic salmon (Salmo salar) in Chile

Abstract

Background: Infectious salmon anaemia (ISA) is a viral disease of marine-farmed Atlantic salmon (Salmo salar) caused by ISA virus (ISAV), which belongs to the genus Isavirus, family Orthomyxoviridae. The virus is considered to be carried by marine wild fish and for over 25 years has caused major disease outbreaks in marine-farmed Atlantic salmon in the Northern hemisphere. In the Southern hemisphere, ISAV was first detected in Chile in 1999 in marine-farmed Coho salmon (Oncorhynchus kisutch). In contrast to the classical presentation of ISA in Atlantic salmon, the presence of ISAV in Chile until now has only been associated with a clinical condition called Icterus Syndrome in Coho salmon and virus isolation has not always been possible. During the winter of 2007, unexplained mortalities were registered in market-size Atlantic salmon in a grow-out site located in Chiloé in Region X of Chile. We report here the diagnostic findings of the first significant clinical outbreak of ISA in marine-farmed Atlantic salmon in Chile and the first characterization of the ISAV isolated from the affected fish.

First field evidence of the evolution from a non-virulent HPR0 to a virulent HPR-deleted infectious salmon anaemia virus

“…Epidemics have occurred in all major Atlantic salmon producing countries including Canada, Chile, the Faroe Islands, Norway, Scotland and the USA, causing severe economic and production losses [1][2][3][4][5][6][7]. The causative agent, infectious salmon anaemia virus (ISAV), belongs to the Orthomyxoviridae family [8].…”

Comparative aspects of infectious salmon anemia virus, an orthomyxovirus of fish, to influenza viruses

“…ISA was fi rst recognized as a disease entity in 1984 in farmed Atlantic salmon (Salmo salar) in Norway [5] and has since been diagnosed in Canada, Scotland, the Faroe Islands, USA and Chile [6][7][8][9]. Fish in the terminal stage were found to be severely anemic, and this feature gave name to the disease.…”

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

“…El primer brote de virus ISA se registró en Noruega en 1984 (Thorud & Djupvik, 1988) y desde entonces la enfermedad se ha registrado en todos los principales países productores de salmón del Atlántico: Canadá (Mullins et al, 1998;Ritchie et al, 2001), Escocia (Rodger et al, 1998;Rowley et al, 1999), Estados Unidos (Maine) (Bouchard et al, 2001), Islas Faroe (Lyngøy, 2003) y Chile (Kibenge et al, 2001;Godoy et al, 2008). La especie más susceptible es el salmón del Atlántico (S. salar), pero también logra sobrevivir e infectar a la trucha de mar (Salmo trutta), trucha arcoiris (Onchorhynchus mykiss) y salmon coho (O. kisutch) (Kibenge et al, 2001), los cuales no manifiestan la enfermedad pero pueden actuar como vectores y reservorios del virus ISA (Nylund et al, 1995Hastein, 1997;Rolland & Nylund, 1998).…”