Piscine orthoreovirus Genotype-1 (PRV-1) in Wild Pacific Salmon of British Columbia, Canada: 2011–2020
Round 1
Reviewer 1 Report
Turcotte et al screened 4,031 wild salmonid fish sampled from British Columbia, Canada for the presence of the PRV-1 virus. Overall a low prevalence of 3.5% of PRV-1 was found between 2011 and 2020, predominantly from the marine environment. Highest prevalence (7.4%) was detected in Chinook salmon, with the authors speculating this could be linked to the long residence time in the Strait of Georgia relative to other Pacific salmon species.
The significance of the findings is unclear, given the literature supports that the virus is largely asymptomatic. Justify the significance of these findings to the fish stocks in the abstract and link to smaller lower condition.
Is there any other supporting data to link co-infection from other routine diagnostic testing conducted on these samples or other studies?
Describe the pathology or lack of within the study samples or other studies from histology etc infected vs non-infected if available?
Please find the following minor suggestions to expand the content, add impact, modify Figures and Suppl Tables for clarity and replace general terms with specific terms throughout. Add more PRV-1 assay details and justify use, and detail health status of stocks if known:
Line 26 The Introduction would benefit from an introductory paragraph on the background to PRV, hosts, then first detection of PRV1, symptoms and significance. Summarise the methods to detect PRV-1 either in Introduction or Methods.
Line 64 fish samples
Line 69 tissue collections
Line 76 40 cm
Line 79 'number' regions
Line 84 tissue samples
Line 101, 152, 161, 222 Table etc upper case?
Line 134, 168 No need to list RNA in full
Line 152 Justify using this method. Performance, specificity, sensitivity relative to known phylogeny. Were known infected tissue controls included?
Line 154 Probe label?, delete 2X
Line 181 are plural
Line 238 Add % prevalence to be clearer
Line 271 Figure 3 is difficult to follow. Label or colour code different regions sampled. Add variable circle sizes for ranges of positive prevalence
Line 291 Include weight and condition in abstract
Line 311, 506 State findings of Morton et al, Bass et al
Suppl Table 1
Define AD/CWT
Ct
Define Neg Ct as a footnote
Suppl Table 2
Include reference of primers
Label details probe dye etc
Name primers from original source, most will have a name and help identify for other workers
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This article is very worthy of understanding PRV-1 prevalence. Some revisions should be needed to publish in Fishes. Especially, In discussion, scientific evidence for suggestions and/or hypotheses regarding PRV-1 transmission is insufficient. Discussion should be revised based on the previous studies on salmonid viruses including PRV-1.
1. The scientific name should be included (L12)
2. L 28: It is preferable to include the additional information for PRV-2 and PRV-3.
3. L 43: “Changes in health management practices”. It should be described in more detail.
4. L 83 – 94: While the head kidney from juvenile was preserved in RNA later, those from the adult sample were not done. Is there a specific reason? And how long stored at -20°C?
5. L 142: It is preferable to include the method for RNA purity check.
6. L 152: “Palacios et al. 2020” is not found in Reference Section. It should be included.
7. L 156: Did you consider the positive result by only qPCR? Even though the criteria of the positive result is defined by Ct value (<40), Nucleotide sequences of qPCR amplicon are important to determine the positive result. If you did sequencing for confirmatory diagnosis, it is preferable to include it in the MS.
8. Figure 2. It is preferable to include viral copies of positive samples.
9. L 376-381: To support this sentence, PRV-1 shedding rate and/or minimum infectious dose and/or transmission trait between susceptible species should be included from related references.
10. L 407 -209; Scientific evidence is a little lack. Relating references should be discussed.
It is preferable to conduct the English editing.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
