Phylogenetic analysis of infectious pancreatic necrosis virus in Ireland reveals the spread of a virulent genogroup 5 subtype previously associated with imports

Ruane, Neil M.; McCleary, Stephen; McCarthy, L J; Henshilwood, Kathleen

doi:10.1007/s00705-014-2307-9

Cited by 17 publications

(20 citation statements)

References 32 publications

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“…This is particularly evident between the Chilean and the North American isolates (WB and DM) within genotype 4, where the clustering of Chilean isolates could suggest the formation of a fifth genotype. Similar tradeassociated transmissions of IPNV have been suggested for isolates from Spain, Japan, Iran, and Ireland, that show a great similarity with reference strains from the sources where these countries have imported salmonid fish and eggs (Cutrín et al 2004, Nishizawa et al 2005, Ruane et al 2009, 2015, Dadar et al 2013. Concordantly, the phylogenetic trees in these studies also showed grouping among the local isolates and the formation of minor clusters within genogroups.…”

Section: Discussionsupporting

confidence: 77%

Detection and phylogenetic analysis of infectious pancreatic necrosis virus in Chile

Tapia¹,

Eissler²,

Torres³

et al. 2015

Dis. Aquat. Org.

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Infectious pancreatic necrosis virus (IPNV) is the etiological agent of a highly contagious disease that is endemic to salmon farming in Chile and causes great economic losses to the industry. Here we compared different diagnostic methods to detect IPNV in field samples, including 3 real-time reverse transcription PCR (qRT-PCR) assays, cell culture isolation, and indirect fluorescent antibody test (IFAT). Additionally, we performed a phylogenetic analysis to investigate the genogroups prevailing in Chile, as well as their geographic distribution and virulence. The 3 qRT-PCR assays used primers that targeted regions of the VP2 and VP1 genes of the virus and were tested in 46 samples, presenting a fair agreement within their results. All samples were positive for at least 2 of the qRT-PCR assays, 29 were positive for cell culture, and 23 for IFAT, showing less sensitivity for these latter 2 methods. For the phylogenetic analysis, portions of 1180 and 523 bp of the VP2 region of segment A were amplified by RT-PCR, sequenced and compared with sequences from reference strains and from isolates reported by previous studies carried out in Chile. Most of the sequenced isolates belonged to genogroup 5 (European origin), and 5 were classified within genogroup 1 (American origin). Chilean isolates formed clusters within each of the genogroups found, evidencing a clear differentiation from the reference strains. To our knowledge, this is the most extensive study completed for IPNV in Chile, covering isolates from sea-and freshwater salmon farms and showing a high prevalence of this virus in the country.

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Section: Discussionsupporting

confidence: 77%

Detection and phylogenetic analysis of infectious pancreatic necrosis virus in Chile

Tapia¹,

Eissler²,

Torres³

et al. 2015

Dis. Aquat. Org.

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“…This strategy has proven to be useful in identifying the origin of disease outbreaks and developing effective control strategies for disease management (Fringuelli et al, 2008; Kristoffersen et al, 2009; Snow, 2011; Lyngstad et al, 2012; Ruane et al, 2015). Herein, we have applied this approach to study the evolutionary and epidemiological dynamics of IHNV and VHSV in Italy, and to identify possible patterns for viral spread.…”

Section: Discussionmentioning

confidence: 99%

Molecular Evolution and Phylogeography of Co-circulating IHNV and VHSV in Italy

et al. 2016

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Infectious haematopoietic necrosis virus (IHNV) and viral haemorrhagic septicaemia virus (VHSV) are the most important viral pathogens impacting rainbow trout farming. These viruses are persistent in Italy, where they are responsible for severe disease outbreaks (epizootics) that affect the profitability of the trout industry. Despite the importance of IHNV and VHSV, little is known about their evolution at a local scale, although this is likely to be important for virus eradication and control. To address this issue we performed a detailed molecular evolutionary and epidemiological analysis of IHNV and VHSV in trout farms from northern Italy. Full-length glycoprotein gene sequences of a selection of VHSV (n = 108) and IHNV (n = 89) strains were obtained. This revealed that Italian VHSV strains belong to sublineages Ia1 and Ia2 of genotype Ia and are distributed into 7 genetic clusters. In contrast, all Italian IHNV isolates fell within genogroup E, for which only a single genetic cluster was identified. More striking was that IHNV has evolved more rapidly than VHSV (mean rates of 11 and 7.3 × 10−4 nucleotide substitutions per site, per year, respectively), indicating that these viruses exhibit fundamentally different evolutionary dynamics. The time to the most recent common ancestor of both IHNV and VHSV was consistent with the first reports of these pathogens in Italy. By combining sequence data with epidemiological information it was possible to identify different patterns of virus spread among trout farms, in which adjacent facilities can be infected by either genetically similar or different viruses, and farms located in different water catchments can be infected by identical strains. Overall, these findings highlight the importance of combining molecular and epidemiological information to identify the determinants of IHN and VHS spread, and to provide data that is central to future surveillance strategies and possibly control.

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“…The clustering together of isolates from one site, renders support to the theory of the existence of “house strains.” Finally, it is noteworthy that the findings in this report relate to Norwegian isolates of IPNV. In Ireland and Scotland, IPNV isolates with P 217 T 221 motifs were associated with clinical outbreaks (Bain et al, 2008; Ruane et al, 2009, 2015). The explanation for this contradiction is not easy to provide although an interesting subject for future research.…”

Section: Discussionmentioning

confidence: 99%

Infectious Pancreatic Necrosis Virus Causing Clinical and Subclinical Infections in Atlantic Salmon Have Different Genetic Fingerprints

Mutoloki

Jøssund²,

Ritchie³

et al. 2016

Front. Microbiol.

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Infectious pancreatic necrosis virus (IPNV) is the causative agent of IPN, an important disease of salmonids. IPNV infections result in either sub-clinical or overt disease and the basis of this difference is not well-understood. The objective of the present study was to determine the VP2 gene of the virus associated with the different forms of clinical manifestation. Groups of Atlantic salmon (Salmo salar L.) reared in farms located in different IPN disease pressures were monitored from brood stock until grow-out over a 3 year period. Hatcheries A1 and B1 as well as cooperating seawater farms were located in a low disease risk area while hatcheries A2 and B2 as well as their cooperating seawater farms were in high IPN risk areas. Samples including eggs, milt, whole fry, kidney depending on the stage of production were collected during outbreaks or in apparently healthy populations where no outbreaks occurred. The virus was re-isolated in CHSE cells and the VP2 gene amplified by RT-PCR followed by sequencing. During the freshwater stage, there were no disease outbreaks at hatcheries A1, A2, and B1 (except in one fish group that originated from hatchery B2), although IPNV was isolated from some of the fish groups at all 3 hatcheries. By contrast, all fish groups at hatchery B2 suffered IPN outbreaks. In seawater, only groups of fish originating from hatchery A1 had no IPN outbreaks albeit virus being isolated from the fish. On the other hand, fish originating from hatcheries A2, B1, and B2 experienced outbreaks in seawater. The VP2 amino acid fingerprint of the virus associated with subclinical infections from A1 and co-operating seawater sites was V64A137P217T221A247N252S281D282E319. By contrast, all virus isolates associated with clinical infections had the motif I64T137T217A221T247V252T281N282A319, where underlined amino acids represent the avirulent and highly virulent motif, respectively. Phylogenetic analysis of amino acid sequences showed 2 clades, one of isolates associated with subclinical infections (from A1 and cooperating seawater farms) and the other of isolates from fish with overt disease (all other sites). Furthermore, the clustering pattern of isolates suggests more circulation of virus within fish groups rather than between them.

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Phylogenetic analysis of infectious pancreatic necrosis virus in Ireland reveals the spread of a virulent genogroup 5 subtype previously associated with imports

Cited by 17 publications

References 32 publications

Detection and phylogenetic analysis of infectious pancreatic necrosis virus in Chile

Detection and phylogenetic analysis of infectious pancreatic necrosis virus in Chile

Molecular Evolution and Phylogeography of Co-circulating IHNV and VHSV in Italy

Infectious Pancreatic Necrosis Virus Causing Clinical and Subclinical Infections in Atlantic Salmon Have Different Genetic Fingerprints

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