Dear Prof Smith,

Thank you very much for submitting your manuscript "Epidemiological insights from a large-scale investigation of intestinal helminths in Medieval Europe." for consideration at PLOS Neglected Tropical Diseases. As with all papers reviewed by the journal, your manuscript was reviewed by members of the editorial board and by several independent reviewers. The reviewers appreciated the attention to an important topic. Based on the reviews, we are likely to accept this manuscript for publication, providing that you modify the manuscript according to the review recommendations.

Two reviewers of your manuscript recommended to accept it after minor revision and I concur. Please see the reviewers comments' in detail and address them point-by-point basis. I expect your revised manuscript in time.

Please prepare and submit your revised manuscript within 30 days. If you anticipate any delay, please let us know the expected resubmission date by replying to this email.  

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[1] A letter containing a detailed list of your responses to all review comments, and a description of the changes you have made in the manuscript. 

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out

[2] Two versions of the revised manuscript: one with either highlights or tracked changes denoting where the text has been changed; the other a clean version (uploaded as the manuscript file).

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Thank you again for your submission to our journal. We hope that our editorial process has been constructive so far, and we welcome your feedback at any time. Please don't hesitate to contact us if you have any questions or comments.

Sincerely,

jong-Yil Chai

Guest Editor

PLOS Neglected Tropical Diseases

Mar Siles-Lucas

Deputy Editor

PLOS Neglected Tropical Diseases

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Two reviewers of your manuscript recommended to accept it after minor revision and I concur. Please see the reviewers comments' in detail and address them point-by-point basis. I expect your revised manuscript in time.

Reviewer's Responses to Questions

Key Review Criteria Required for Acceptance?

As you describe the new analyses required for acceptance, please consider the following:

Methods

-Are the objectives of the study clearly articulated with a clear testable hypothesis stated?

-Is the study design appropriate to address the stated objectives?

-Is the population clearly described and appropriate for the hypothesis being tested?

-Is the sample size sufficient to ensure adequate power to address the hypothesis being tested?

-Were correct statistical analysis used to support conclusions?

-Are there concerns about ethical or regulatory requirements being met?

Reviewer #1: If the authors were to further define their methods, then this paper would be an especially valuable source. How were the eggs concentrated for analysis? Were the slides examined without concentrating the eggs? Were the sediment samples collected from the sacra? Were control samples analyzed from the cemeteries? Why were the microscopic preparations discarded? Where are the initial samples now stored?

Reviewer #2: The methods are clearly defined, however there are located after the discussion section, it is necessary to move them after the results section. The study design is appropriate as well as the sample size.

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Results

-Does the analysis presented match the analysis plan?

-Are the results clearly and completely presented?

-Are the figures (Tables, Images) of sufficient quality for clarity?

Reviewer #1: The results are well-organized and succinct

Reviewer #2: Results are clear and following the study design. The figures are sufficient but a couple of tables could help the results presentation and summary, for example the prevalence of helminths in the different study sites.

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Conclusions

-Are the conclusions supported by the data presented?

-Are the limitations of analysis clearly described?

-Do the authors discuss how these data can be helpful to advance our understanding of the topic under study?

-Is public health relevance addressed?

Reviewer #1: The conclusions and discussion are adequate.

I think that basic scholarship could be improved by citing the following:

Camacho et a1 (2018) Recovering parasites from mummies and coprolites: an epidemiological approach. Parasites & Vectors (2018) 11:248

https://doi.org/10.1186/s13071-018-2729-4

This paper addresses and introduces a paleoepidemiological approach to archaeological parasitology.

Leles et al (2010) A parasitological paradox: Why is ascarid infection so rare in the prehistoric Americas? J Archaeol Sci. 2010;37:1510–20.

This paper summarized all reports from Europe to assess the commonness of geohelminth infection compared to other prehistoric records and developed reasons for the high soil transmitted parasite experience in Europe.

Replace Reinhard KJ. Parasitology as an Interpretive Tool in Archaeology. Am Antiquity. 644 1992;57(2):231-45

with Reinhard, K., 2017. Reestablishing rigor in archaeological parasitology. International journal of paleopathology, 19, pp.124-134.

The 1992 reference is antiquated and the 2017 paper takes on issues that are current.

Reviewer #2: The conclusions are supported by the data and analysis undertaken. Limitations are mentioned in some parts but not clearly expressed. In some parts, such as page 24 line 387, there is a repetition of results which is not needed.

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Editorial and Data Presentation Modifications?

Use this section for editorial suggestions as well as relatively minor modifications of existing data that would enhance clarity. If the only modifications needed are minor and/or editorial, you may wish to recommend “Minor Revision” or “Accept”.

Reviewer #1: Here are optional suggestions for the manuscript.

“Prevalence”, in parasitology parlance, refers to the total number of individuals in a population are infected at a specific period of time, usually expressed as a percentage of the population. In the case of this paper, prevalence is the number/percentage of interments positive for infection evidence. I suggest that prevalence as used by the authors be defined in the Introduction.

Reviewer #2: Minor English revision is needed in the document

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Summary and General Comments

Use this section to provide overall comments, discuss strengths/weaknesses of the study, novelty, significance, general execution and scholarship. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. If requesting major revision, please articulate the new experiments that are needed.

Reviewer #1: This paper could be published as is. It is a very significant, novel approach to assessing paleoepidemiology for Europe. It represents a monumental amount of work and innovative integration of standard microscopy and molecular biology. It established cemetery analysis as a statistically reliable manner of collecting hundreds of data points. Thus, based on this research, burial analysis takes its place alongside shaft feature analysis as key approach to defining infection across cultures, time and geography. It fits into an emerging realization that, for the Eurasian continent, Europe had a unique parasite pattern defined by geohelminths. Geographically, this pattern is not found in central Russia and westward. Therefore, Europe was an endemic area characterized by remarkably lax sanitation and hygiene controls.

Reviewer #2: In summary is well designed, implemented and presented. However, there are some statements that need further evidence or references for support, such as the one in lines 549-464. The study does provide with helpful epidemiological insights to intestinal helminths that could be useful in certain endemic regions.

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Reviewer #1: Yes: Karl J. Reinhard

Reviewer #2: No

Figure Files:

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org.

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Dear Prof Smith,

We are pleased to inform you that your manuscript 'Epidemiological insights from a large-scale investigation of intestinal helminths in Medieval Europe.' has been provisionally accepted for publication in PLOS Neglected Tropical Diseases.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow up email. A member of our team will be in touch with a set of requests.

Please note that your manuscript will not be scheduled for publication until you have made the required changes, so a swift response is appreciated.

IMPORTANT: The editorial review process is now complete. PLOS will only permit corrections to spelling, formatting or significant scientific errors from this point onwards. Requests for major changes, or any which affect the scientific understanding of your work, will cause delays to the publication date of your manuscript.

Should you, your institution's press office or the journal office choose to press release your paper, you will automatically be opted out of early publication. We ask that you notify us now if you or your institution is planning to press release the article. All press must be co-ordinated with PLOS.

Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Neglected Tropical Diseases.

Best regards,

jong-Yil Chai

Guest Editor

PLOS Neglected Tropical Diseases

Mar Siles-Lucas

Deputy Editor

PLOS Neglected Tropical Diseases

***********************************************************

Your revised manuscript has been reviewed by referees. Both of them recommended to accept your manuscript as it is and I concur. Your cooperation with PLoS NTD is highly appreciated.

Reviewer's Responses to Questions

Key Review Criteria Required for Acceptance?

As you describe the new analyses required for acceptance, please consider the following:

Methods

-Are the objectives of the study clearly articulated with a clear testable hypothesis stated?

-Is the study design appropriate to address the stated objectives?

-Is the population clearly described and appropriate for the hypothesis being tested?

-Is the sample size sufficient to ensure adequate power to address the hypothesis being tested?

-Were correct statistical analysis used to support conclusions?

-Are there concerns about ethical or regulatory requirements being met?

Reviewer #1: The revised paper includes improvements of the methods description.

Reviewer #2: The observations from the methods section were correctly addressed

**********

Results

-Does the analysis presented match the analysis plan?

-Are the results clearly and completely presented?

-Are the figures (Tables, Images) of sufficient quality for clarity?

Reviewer #1: The results are clear and concise.

Reviewer #2: The observations from the results section were correctly answered

**********

Conclusions

-Are the conclusions supported by the data presented?

-Are the limitations of analysis clearly described?

-Do the authors discuss how these data can be helpful to advance our understanding of the topic under study?

-Is public health relevance addressed?

Reviewer #1: The conclusions address all four of these goals successfully.

Reviewer #2: The observations made in this section were correctly addressed

**********

Editorial and Data Presentation Modifications?

Use this section for editorial suggestions as well as relatively minor modifications of existing data that would enhance clarity. If the only modifications needed are minor and/or editorial, you may wish to recommend “Minor Revision” or “Accept”.

Reviewer #1: The revision needs no modification od data presentation.

Reviewer #2: Accept

**********

Summary and General Comments

Use this section to provide overall comments, discuss strengths/weaknesses of the study, novelty, significance, general execution and scholarship. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. If requesting major revision, please articulate the new experiments that are needed.

Reviewer #1: The revision addresses the reviewer comments perfectly.

Reviewer #2: There are no new comments

**********

PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Karl J Reinhard

Reviewer #2: No