Occurrence of salmonid alphavirus (SAV) and piscine orthoreovirus (PRV) infections in wild sea trout Salmo trutta in Norway

Madhun, Abdullah Sami; Isachsen, Cecilie Helen; Omdal, Linn Maren; Einen, Ann Cathrine Bårdsgjære; Bjørn, Pål Arne; Nilsen, Rune; Karlsbakk, Egil

doi:10.3354/dao03009

Cited by 13 publications

(16 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The probability of wild salmon being exposed to SAV from farms escapees was therefore low both when leaving the coast as smolts (2010–2011) and when returning as adults in 2012. The absence of SAV in the salmon tested is also consistent with previous findings that SAV infections are uncommon in wild salmonids irrespective of farming intensity or the frequency of PD outbreaks at the locations examined (Biering et al., ; Garseth et al., ; Madhun et al., ; Plarre & Nylund, ).…”

Section: Resultssupporting

confidence: 89%

Prevalence of piscine orthoreovirus and salmonid alphavirus in sea‐caught returning adult Atlantic salmon (Salmo salar L.) in northern Norway

Madhun

Isachsen

Omdal

et al. 2018

Journal of Fish Diseases

Self Cite

View full text Add to dashboard Cite

Heart and skeletal muscle inflammation (HSMI) caused by piscine orthoreovirus (PRV) and pancreas disease (PD) caused by salmonid alphavirus (SAV) are among the most prevalent viral diseases of Atlantic salmon farmed in Norway. There are limited data about the impact of disease in farmed salmon on wild salmon populations. Therefore, the prevalence of PRV and SAV in returning salmon caught in six sea sites was determined using real-time RT-PCR analyses. Of 419 salmon tested, 15.8% tested positive for PRV, while none were positive for SAV. However, scale reading revealed that 10% of the salmon had escaped from farms. The prevalence of PRV in wild salmon (8%) was significantly lower than in farm escapees (86%), and increased with fish length (proxy for age). Sequencing of the S1 gene of PRV from 39 infected fish revealed a mix of genotypes. The observed increase in PRV prevalence with fish age and the lack of phylogeographic structure of the virus could be explained by virus transmission in the feeding areas. Our results highlight the need for studies about the prevalence of PRV and other pathogens in Atlantic salmon in its oceanic phase. Disease outbreaks in salmon farms may lead to increased infection and disease risks at neighbouring farms and in wild fish populations, and there is an increasing public concern of disease impacting wild salmon populations in Norway (Sv asand et al., 2017). Data are collected annually on the frequency and geographical distribution of disease outbreaks in fish farms (Hjeltnes et al., 2017). Correlating such data from regions differing in farming intensities and disease profiles with pathogen prevalence in local wild salmon populations would thus help to address this concern. However, pathogen prevalence data alone as an indicator of infection pressure have ----------------------------------------------------This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

show abstract

Section: Resultssupporting

confidence: 89%

Prevalence of piscine orthoreovirus and salmonid alphavirus in sea‐caught returning adult Atlantic salmon (Salmo salar L.) in northern Norway

Madhun

Isachsen

Omdal

et al. 2018

Journal of Fish Diseases

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the second study, sampling of brown trout took place in hatcheries: Given that the virus is present in a nonanadromous brown trout reservoir, it is more likely to be found in a hatchery where fish are kept together in tanks where transmission of pathogens between individuals is facilitated. The overall prevalence of PCR‐positive nonanadromous brown trout in this study was at par with previous studies in wild sea trout (Biering et al., ; Garseth, Fritsvold et al., ; Madhun et al., ). In previous studies, the viral loads (judged by C t values) have been low in all but one PRV‐positive trout.…”

Section: Discussionsupporting

confidence: 83%

Little evidence to suggest salmonid freshwater reservoirs of piscine orthoreovirus (PRV)

Garseth

Biering

2018

Journal of Fish Diseases

View full text Add to dashboard Cite

“…None of the PRV‐3 positive seatrout selected for PRV‐1 analyses were PCR‐positive. Previous studies have shown that approximately 1%–3% of seatrout are PRV‐1‐positive (Garseth, Fritsvold, Opheim, Skjerve, & Biering, ; Madhun et al, ), but only one case had viral loads sufficiently high to enable sequencing and phylogenetic analyses. In that case, the sequence grouped together with PRV‐1 from wild and farmed salmon (Garseth et al, ).…”

Section: Discussionmentioning

confidence: 99%

Piscine orthoreovirus‐3 is prevalent in wild seatrout (Salmo trutta L.) in Norway

Garseth

Moldal

Gåsnes

et al. 2019

Journal of Fish Diseases

View full text Add to dashboard Cite

In 2017, a PCR‐based survey for Piscine orthoreovirus‐3 (PRV‐3) was conducted in wild anadromous and non‐anadromous salmonids in Norway. In seatrout (anadromous Salmo trutta L.), the virus was present in 16.6% of the fish and in 15 of 21 investigated rivers. Four of 221 (1.8%) Atlantic salmon (Salmo salar L.) from three of 15 rivers were also PCR‐positive, with Ct‐values indicating low amounts of viral RNA. All anadromous Arctic char (Salvelinus alpinus L.) were PCR‐negative. Neither non‐anadromous trout (brown trout) nor landlocked salmon were PRV‐3 positive. Altogether, these findings suggest that in Norway PRV‐3 is more prevalent in the marine environment. In contrast, PRV‐3 is present in areas with intensive inland farming in continental Europe. PRV‐3 genome sequences from Norwegian seatrout grouped together with sequences from rainbow trout (Oncorhynchus mykiss Walbaum) in Norway and Coho salmon (Oncorhynchus kisutch Walbaum) in Chile. At present, the origin of the virus remains unknown. Nevertheless, the study highlights the value of safeguarding native fish by upholding natural and artificial barriers that hinder introduction and spread, on a local or national scale, of alien fish species and their pathogens. Accordingly, further investigations of freshwater reservoirs and interactions with farmed salmonids are warranted.

show abstract

Occurrence of salmonid alphavirus (SAV) and piscine orthoreovirus (PRV) infections in wild sea trout Salmo trutta in Norway

Cited by 13 publications

References 13 publications

Prevalence of piscine orthoreovirus and salmonid alphavirus in sea‐caught returning adult Atlantic salmon (Salmo salar L.) in northern Norway

Prevalence of piscine orthoreovirus and salmonid alphavirus in sea‐caught returning adult Atlantic salmon (Salmo salar L.) in northern Norway

Little evidence to suggest salmonid freshwater reservoirs of piscine orthoreovirus (PRV)

Piscine orthoreovirus‐3 is prevalent in wild seatrout (Salmo trutta L.) in Norway

Contact Info

Product

Resources

About