Outbreak of viral haemorrhagic septicaemia (VHS) in lumpfish (Cyclopterus lumpus) in Iceland caused by VHS virus genotype IV

Abstract

A novel viral haemorrhagic septicaemia virus (VHSV) of genotype IV was isolated from wild lumpfish (Cyclopterus lumpus), brought to a land‐based farm in Iceland, to serve as broodfish. Two groups of lumpfish juveniles, kept in tanks in the same facility, got infected. The virus isolated was identified as VHSV by ELISA and real‐time RT‐PCR. Phylogenetic analysis, based on the glycoprotein (G) gene sequences, may indicate a novel subgroup of VHSV genotype IV. In controlled laboratory exposure studies with this new isolate, there was 3% survival in the I.P. injection challenged group while there was 90% survival in the immersion group. VHSV was not re‐isolated from fish challenged by immersion. In a cohabitation trial, lumpfish infected I.P. (shedders) were placed in tanks with naïve lumpfish as well as naïve Atlantic salmon (Salmo salar L.). 10% of the lumpfish shedders and 43%–50% of the cohabiting lumpfish survived after 4 weeks. 80%–92% of the Atlantic salmon survived, but no viral RNA was detected by real‐time RT‐PCR nor VHSV was isolated from Atlantic salmon. This is the first isolation of a notifiable virus in Iceland and the first report of VHSV of genotype IV in European waters.

Lumpfish (Cyclopterus lumpus, Linnaeus) is susceptible to viral nervous necrosis: Result of an experimental infection with different genotypes of Betanodavirus

“…New diseases and infectious agents inevitably emerge when new species are introduced to aquaculture, and the lumpfish appears to pose no exception to this rule. A range of different pathogens has been detected in wild and farmed lumpfish, including viruses, bacteria, parasites and fungi (Alarcón, Gulla, et al, 2016;Alarcón, Thoen, et al, 2016;Guðmundsdóttir et al, 2019;Hjeltnes, 2014;Johansen, 2013;Marcos-López, Donald, Stagg, & McCarthy, 2013;Poppe et al, 2012;Scholz et al, 2017;Scholz, Ruane, Marcos-Lopez, et al, 2018;Skoge, Brattespe, Økland, Plarre, & Nylund, 2018;Stagg et al, 2017;Treasurer & Birkbeck, 2018). Finally, the possible role of cleaner fish as subclinical carrier for viral disease has emerged (Rimstad Basic, Gulla, & Hjeltnes & Mortensen, 2017).…”

Isolation and identification of a viral haemorrhagic septicaemia virus (VHSV) isolate from wild largemouth bass Micropterus salmoides in China

“…Immersion is most representative of the natural way of infection, but it needs long exposure time and high viral titre. Compared to immersion infection, intraperitoneal injection trial tends to show a fast and high lethality (Guðmundsdóttir et al, ; Ou, Zhu, Chen, & Zhang, ). In the present study, intraperitoneal injection of VHSVLB2018 caused high cumulative mortalities in infection groups at 7 days.…”

“…Rhabdoviruses, associated with severe haemorrhagic disease, have been reported to cause significant mortality and morbidity in both wild and cultured fish worldwide (Bedendo et al, ; Skall, Olesen, & Mellergaard, ). Viral haemorrhagic septicaemia virus (VHSV), a member of the family Rhabdoviridae, genus Novirhabdovirus , was firstly isolated in Europe from rainbow trout (Jensen, ), later in North America, Northeast Asia and Iceland (Guðmundsdóttir et al, ; Skall et al, ). VHSV has been found in more than 80 different fish species, including economically important fish such as the Rainbow trout (Romero, Dios, Bremont, Figueras, & Novoa, ), Japanese flounder (Isshik, Nishizawa, Kobayashi, Nagano, & Miyazaki, ) and Pacific herring (Lovy et al, ).…”

“…It has been reported that the VHSV genotypes I, II and III include the virus isolates originating mainly from continental Europe (Thiéry et al, 2002), Baltic Sea (Snow et al, 2004) and the North Atlantic (López-Vázquez et al, 2006), respectively. Genotype IV consists of VHSV isolates recovered from the North America, Asia and Iceland (Guðmundsdóttir et al, 2019;Lumsden et al, 2007;Nishizawa et al, 2002).…”

“…It has been known that VHSV primarily originates from the marine environment, and wild fish species have been regarded as the main carriers of VHSV (Einer-jensen et al, 2004;Kim, Choi, Kim, & Oh, 2013). VHSV of all genotypes has been identified in various fish species, such as lumpfish (Cyclopterus lumpus), wrasse (Labridae) and red mullet (Mullus barbatus) (Guðmundsdóttir et al, 2019;Ogut & Altuntas, 2014;Skall et al, 2005;Wallace et al, 2015). In the present study, we performed a survey of VHSV in wild fish in the coastal area of the Pearl River Estuary in China, an important area of freshwater that flows into the South China Sea.…”