Dear Dr Ojurongbe,

Thank you very much for submitting your manuscript "Epidemiology of mixed urogenital and intestinal schistosomiasis among school children in two endemic communities of Southern Nigeria" 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. In light of the reviews (below this email), we would like to invite the resubmission of a significantly-revised version that takes into account the reviewers' comments.

We cannot make any decision about publication until we have seen the revised manuscript and your response to the reviewers' comments. Your revised manuscript is also likely to be sent to reviewers for further evaluation.

When you are ready to resubmit, please upload the following:

[1] A letter containing a detailed list of your responses to the 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).

Important additional instructions are given below your reviewer comments.

Please prepare and submit your revised manuscript within 60 days. If you anticipate any delay, please let us know the expected resubmission date by replying to this email. Please note that revised manuscripts received after the 60-day due date may require evaluation and peer review similar to newly submitted manuscripts.

Thank you again for your submission. 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,

Mike J Doenhoff

Associate Editor

PLOS Neglected Tropical Diseases

Christine Budke

Deputy Editor

PLOS Neglected Tropical Diseases

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

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 methods used are ok, but my worry is on the sample collection.

Reviewer #2: The objectives of the study are not clear.

In the methods, the authors do not explain why the study was conducted only in school children. In the results, two groups are presented according to age, but in the methods this division is not presented.

The collection of only one urine sample and one stool sample for each student may have limited the finding of positive samples in the study: why is this point not discussed by the authors?

The samples were collected from two communities, but the results are presented as a single sample. What is the reason for this choice? Was the prevalence similar in both communities? For both species of Schistosoma?

In the statistical analysis, was a normality test applied to the sample to choose the appropriate comparison test between the variables.

It is known that the intensity of schistosoma infection is affected by different factors, and not just age and sex. Variables such as hygiene habits, number and time of exposure to water collections, sanitation, previous infection and previous parasitic treatment, could also have been analyzed in the epidemiological study. Why were they not analyzed?

The absence of morbidity analysis in co-infection is a limiting factor in the study.

The authors gave no information about the study period.

Reviewer #3: The objectives of the study are not clearly articulated

The study design is not described

Though the sample size is big enough, the population is only partially described

the sample size is big enough

The statistical analysis is not appropriately reported

There are no ethical issues

--------------------

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 analysis are okay and the results presented well. The issue is on the signs on table 2 which were not explained

Reviewer #2: The figures shown are not in high resolution. The variables that present significant results could be presented in the figure itself and not in the legend.

Table 3 is confused for the interpretation of the results.

It is necessary to explain the set of abbreviations: 'ectopic Sm/Sh' and 'ectopic Sm/Sh/Sm'

Reviewer #3: No specific comments

--------------------

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: Authors should remove sections on hybridization as pointed out in the text

All my other comments are inserted as notes in the text

Reviewer #2: When introducing the manuscript, the authors point out that hybridization between schistosoma species has not yet been reported in Africa (line 79). However, in lines 238 and 239 of the discussion, they present 2 studies that report the ectopic presence of schistosoma eggs in Cameroon (reference 14) and Senegal (reference 33). It may therefor be appropriate to rewrite the introduction paragraph.

The discussion of the article should be reviewed. It is superficial and limited.

At the beginning of the article, the authors suggest that the encounter of ectopic eggs is unprecedented in the study area. But throughout the article, there is decreasing emphasis on this observation and the discussion does not present a differential result. If it is really an unprecedented result, I recommend modifying the article to highlight this finding.

As this is an epidemiological study, it would be interesting to add a paragraph on the importance of the findings for local public health, according to the guidelines for coping with schistosomiasis as an important public health problem by the WHO.

Reviewer #3: The limitations are not clearly described

--------------------

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: Minor revision

Reviewer #2: (No Response)

Reviewer #3: (No Response)

--------------------

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 study is good and deserves publication, however the authors should revise the use of words "impact" since the study is basically about prevalence

Reviewer #2: (No Response)

Reviewer #3: The manuscript entitled "Epidemiology of mixed urogenital and intestinal schistosomiasis among school children in two endemic communities of Southern Nigeria"submitted by Ojo et al. is important, and could give insight into the Schistosomiasis control challenges in areas where both major species are endemic.

However, the manuscript has a substantial limitations which the authors have to address prior any further consideration.

While the title clearly indicates an epidemiological study, there is no clear study design and nor any sampling frame which may permit a validation of the findings. The sites description indicated a previous study reporting the presence of S. hematobium, in urine and not the S. mansoni species. The statistical test used to test association, is not reported appropriately. All together the manuscript requires a deep revision.

In details:

Abstract section:

It is not clear what the authors called "ectopic egg": for non experts in schistosomiasis a brief explanation is required here.

The study design and methodology are missing, as well as brief study procedures, as appropriate in the Abstract.

Prevalence and intensity are confusedly reported and should be separated.

Would hematuria have been associated with S. hematobium?

Introduction Section:

• There is poor background information regarding clinical or epidemiological consequences of co-infection of S.h /S.m as well as ectopic eggs. Please provide more information to justify the research question.

MM section:

• Study design is missing

• Sample size calculation and sample collection should be separated

• Study procedure as well as inclusion and exclusion criteria are missing

• While the sample size calculated was 289, the authors recruited 466 participants: is there an explanation?

• Is there any reason for use of sterile container to collect stool and urine?

Results section:

• What does '5gm' mean?

• Will mixed infection Sh/Sm differ from Sm/Sh?

• Can author provide the odds CI:95% of hematuria in S.h positive versus S.h negative?

Discussion Section

1. Authors should cross check the p-value which should be <0.05 instead of >0.05

2. Authors should provide more specific information on lower liver morbidity and higher bladder morbidity

3. What do the authors mean by this: "Consequently, the collection of urine specimens and their examination may not be necessary in the classification of communities according to the level of endemicity of urinary schistosomiasis".?

--------------------

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: Prof Sammy Olufemi Sam-Wobo

Reviewer #2: No

Reviewer #3: 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.

Data Requirements:

Please note that, as a condition of publication, PLOS' data policy requires that you make available all data used to draw the conclusions outlined in your manuscript. Data must be deposited in an appropriate repository, included within the body of the manuscript, or uploaded as supporting information. This includes all numerical values that were used to generate graphs, histograms etc.. For an example see here: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001908#s5.

Reproducibility:

To enhance the reproducibility of your results, PLOS recommends that you deposit laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see https://journals.plos.org/plosntds/s/submission-guidelines#loc-methods

Attachments

Attachment

Submitted filename: Reviewer - PNTD-D-20-01655_reviewer.pdf

Dear Dr Ojurongbe,

Thank you very much for submitting your manuscript "Prevalence of urogenital and intestinal schistosomiasis among school children in South-west Nigeria" 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.

The authors have made extensive amendments to the manuscript, following referees' suggestions.

I have re-read the manuscript and incorporated/suggested a few minor alterations, most of which can probably be attended to in-house.

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.

When you are ready to resubmit, please upload the following:

[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).

Important additional instructions are given below your reviewer comments.

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,

Mike J Doenhoff

Associate Editor

PLOS Neglected Tropical Diseases

Christine Budke

Deputy Editor

PLOS Neglected Tropical Diseases

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

The authors have made extensive amendments to the manuscript, following referees' suggestions.

I have re-read the manuscript and incorporated/suggested a few minor alterations, most of which can probably be attended to in-house.

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.

Data Requirements:

Please note that, as a condition of publication, PLOS' data policy requires that you make available all data used to draw the conclusions outlined in your manuscript. Data must be deposited in an appropriate repository, included within the body of the manuscript, or uploaded as supporting information. This includes all numerical values that were used to generate graphs, histograms etc.. For an example see here: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001908#s5.

Reproducibility:

To enhance the reproducibility of your results, we recommend that you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. Additionally, PLOS ONE offers an option to publish peer-reviewed clinical study protocols. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols

References

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article's retracted status in the References list and also include a citation and full reference for the retraction notice.

Attachments

Attachment

Submitted filename: Ojo et al_Revised_Changes highlited.docx

Dear Dr Ojurongbe,

We are pleased to inform you that your manuscript 'Prevalence of urogenital and intestinal schistosomiasis among school children in South-west Nigeria' 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,

Mike J Doenhoff

Associate Editor

PLOS Neglected Tropical Diseases

Christine Budke

Deputy Editor

PLOS Neglected Tropical Diseases

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