Dear Stephane Ranque,

Thank you very much for submitting your manuscript "Identification of Bulinus forskalii as a potential intermediate host of Schistosoma hæmatobium in Senegal" 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 independent and expertise 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.

Your manuscript has been assessed by 3 expertise reviewers in schistosomiasis research. The manuscript reports the novel information of Bulinus forskalii snail and its potential to be S. haematobium intermediate host in the endemic area. Even through, there is no additional experiments suggested from reviewers, but there are major concerns of the sample size and insufficient statistic used in the current version. All the reviewers suggested to improve the statistic used in the study along with other questions/comments to clarify the materials and methods, and result sections. Additional information in the introduction especially MALDI-TOF MS including the related-references will improve the manuscript as well.

Please clarify the reviewer comments, suggestions and/or questions, then and address them point-by-point that would improve the manuscript.

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,

Wannaporn Ittiprasert, Ph.D

Academic Editor

PLOS Neglected Tropical Diseases

Makedonka Mitreva

Section Editor

PLOS Neglected Tropical Diseases

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

PNTD-D-22-00788

Identification of Bulinus forskalii as a potential intermediate host of Schistosoma haematobium in Senegal

Dear Dr. Stephane Ranque,

Thank you for submitting your manuscript ‘Identification of Bulinus forskalii as a potential intermediate host of Schistosoma haematobium in Senegal’ to PLoS NTD. Your manuscript has been assessed by 3 expertise reviewers in schistosomiasis research. The manuscript reports the novel information of Bulinus forskalii snail and its potential to be S. haematobium intermediate host in the endemic area. Even through, there is no additional experiments suggested from reviewers, but there are major concerns of the sample size and insufficient statistic used in the current version. All the reviewers suggested to improve the statistic used in the study along with other questions/comments to clarify the materials and methods, and result sections. Additional information in the introduction especially MALDI-TOF MS including the related-references will improve the manuscript as well.

Please clarify the reviewer comments, suggestions and/or questions, then and address them point-by-point that would improve the manuscript.

Best regards,

Wannaporn Ittiprasert, Ph.D

PLoS NTD

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: (No Response)

Reviewer #2: -Are the objectives of the study clearly articulated with a clear testable hypothesis stated?

The objectives and hypothesis have been implicitly stated. These could be explicitly stated in an additional paragraph in the introduction.

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

Yes.

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

While the study focuses on B. forskalii, inclusion and/or discussion of other snail species found in the field sampling area would strengthen the manuscript.

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

Yes, assuming the hypothesis is something to the effect of "B. forskalii snails that reside in the delta region of the Senegal River can carry S. haematobium infections". The current study conducted experiments on a smaller scale in terms of geographical location compared to other referenced studies of intermediate hosts of Schistosoma parasites.

-Were correct statistical analysis used to support conclusions?

No statistical analyses were described. Perhaps there could be a test to correlate cercarial shedding to Ct value or COX1 and ITS2 (yes/no) status.

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

No, there are no ethical or regulatory concerns.

-Other comments

Consider adding information to the methods section to answer the following questions: How was the cercarial shedding test done? How was the DNA extracted? How was the RT-PCR conducted? How was the PCR sequencing conducted?

Reviewer #3: P.M. Gaye et al build on their previous work from 2021 where they use MALDI-TOF MS to identify host snails. Here they collect 55 Bu forskalli from the Senegal river delta and look for evidence of S.haemotobium infection. The methods section of the paper is not sufficient to describe their study, but can be easily improved upon.

1) Please describe in more detail the area of the delta where the Bu forskalli was collected; a map may be helpful here.

2) Include in your methods how the snails were held (under what conditions) until the experiment to determine the presence of Sh or other parasites.

3) Describe your shedding protocol. How were the cercariae induced from the Bu forskalli?

4) On line 75, the authors tell us they used a reference spectra database and provide the link. Please describe this database as it was not intuitive and this Reviewer could not find the relevant page for snail references.

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

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: Improve figure 1 quality.

Reviewer #2: -Does the analysis presented match the analysis plan?

Yes.

-Are the results clearly and completely presented?

As suggested below, more of the data could be made available, such as the results for all 55 B. forskalii specimens in Table 1.

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

Yes. See below for suggestions.

Figure 2: If possible, consider showing (or explicitly labeling) the MALDI-TOF MS spectra of the reference sample for B. forskalii and, if available, those of other Bulinus members. Also consider showing the corresponding log score values for each spectra.

Table 1: The text describes 55 samples, while this table shows 10. How were these chosen? Are these specimens that met the Ct cutoff of 35 for the RT-PCR? Consider clarifying this in the text and/or caption. These results also do not show completely uninfected specimens, that is, specimens with a negative shedding test, CT>35, and negative sequencing results for COX1 and ITS2. Perhaps there were some, but they are not shown in the table? Consider including the data for all tested specimens, if not in this table, as supplementary information.

-Other comments

On line 67, the manuscript states that "[the authors] collected (n=55) snails from the Senegal River Delta area, identified as B. forskalii". Were there other Bulinus snail species present but not considered for analysis? While perhaps outside the scope of the study, such information might help describe the contribution of B. forskalii relative to other Bulinus species as an intermediate host for S. haematobium.

Reviewer #3: The authors claim in their results that the Bu forskalli were identified using MALDI-TOF MS, but also confirmed by COX-Folmer. Can they include that data in this manuscript?

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

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: (No Response)

Reviewer #2: -Are the conclusions supported by the data presented?

Yes.

-Are the limitations of analysis clearly described?

Yes.

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

There could be more discussion about how this new knowledge that B. forskalii can carry S. haematobium infection can help improve epidemiological studies, surveillance efforts, and contribute to controlling schistosomiasis. For example, in surveillance studies, have researchers previously dismissed the possibility that B. forskalii snails could carry S. haematobium, and thus would assess a region to be at low risk of S. haematobium infections if only B. forskalii were found? If so, the findings in this study would encourage researchers to re-evaluate the guidelines for this hypothetical assessment.

-Is public health relevance addressed?

Yes, but, as suggested above, it could be more thoroughly discussed.

-Other comments

On line 112, the text asserts "Our findings demonstrate that B. forskalii can be parasitised by S. hæmatobium complex fluke, in particular, S. hæmatobium s.s., S. bovis s.s., and hybrids between them." The results do not necessarily demonstrate that S. haematobium x S. bovis hybrid species were detected in these snails. As stated on line 124, "discrepant ITS and COX-based identification in a given snail specimen can be interpreted either as an infection with one hybrid parasite or a co-infection with two distinct parasite species." Consider slightly modifying the statement to the effect of "Our findings demonstrate that B. forskalii can be parasitised by S. hæmatobium complex fluke, in particular, S. hæmatobium s.s., S. bovis s.s., and possibly S. haematobium x S. bovis hybrids."

Reviewer #3: The authors' conclusions are supported by the data presented.

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

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: Introduction:

There is some data of B. forskalii and B. senegalensis distribution in Senegal? If so consider adding this information as it is extremely relevant to this study as some of B. senegalensis could be misidentified due to the similarity of the species.

I suggest you add some information about the MALDI-TOF MS as a research tool and its relevance to several species’ identification.

Maybe you can add a sentence with the relevance of the present study at the end of the introduction.

Methods:

Since according to Hamlili FZ et. al, 2021 it is necessary a specific database depending on the storage condition and can impact the quality of the tool I suggest you indicate the storage condition performed in the present study. You can indicate that the methods were performed as Hamlili FZ et. al, 2021, but quickly describe it.

The same I can point to the other methods - genomic DNA extraction, nucleotide sequence-based analysis, Real-time-Polymerase Chain Reaction (RT-PCR), and PCR sequencing - readers need to know exactly the methods you performed (reproducible study).

Results:

What is the relevance of the MALDI-TOF MS technique if the identification differentiation between B. forskalii and B. senegalensis can be performed by molecular identification using the COI gene?

To improve the results view and comparison I think that characteristic MALDI-TOF MS spectra acquired from B. senegalensis feet should be added to the Figure 1 as a control.

Can the infected snails be different from the non-infected under the MALDI-TOF MS analysis?

Reviewer #2: Line 70: "Desoxyribo" should be Deoxyribo

Line 72: ".. of Flight (MALDI-TOF MS)": Consider ".. of Flight Mass Spectrometry (MALDI-TOF MS)"

Line 31: "Nucleotide sequence analysis identified 6 (11.0%), using COX1, and 3 (5.5%), using ITS2, S. hæmatobium, and 3 (5.5%) S. bovis" could be clarified to something to the effect of "Nucleotide sequence analysis identified 6 (11.0%) using COX1 and 3 (5.5%) using ITS2 for S. hæmatobium, and 3 (5.5%) using COX1 and 3 (5.5%) using ITS2 for S. bovis"

On line 32, the manuscript asserts that "This result is the first report of infection of B. forskalii by S. hæmatobium complex parasites." However, the study by Labbo and coworkers (reference 19) have previously reported B. forskalii with S. haematobium infection. The statement could be modified by appending "in Senegal" or otherwise rewritten to reflect that the current study, in contrast to the previous study, uses more precise methods to differentiate between B. forskalii and B. senegalensis in identifying B. forskalii infected with S. haematobium.

Reviewer #3: The paper is well written; no editorial suggestions.

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

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 present study is relevant since it is the first report of B. forskalii infected by S. hæmatobium complex parasites in Senegal. Although it improves the knowledge about host-parasite interactions it also highlights that more similar studies should be held in endemic sites to better understand the transmission of Schistosoma species. It is relevant that MALDI-TOF mass spectrometry analysis was applied again as a tool that allows the differential identification of B. forskalii and B. senegalensis snails since B. senegalensis is already one of the main intermediate hosts of S. hæmatobium.

Reviewer #2: -Summary of study

The manuscript describes a study of 55 B. forskalii snails with respect to S. haematobium and S. bovis infection in the delta region of the Senegal River in September 2020. The study addresses the challenge of differentiating B. forskalii and B. senegalensis by using MALDI-TOF MS and PCR sequencing (COX-Folmer primers) analyses and follows with a cercarial shedding test and PCR sequencing analyses for S. haematobium COX1 and ITS2, showing that B. forskalii of this region can carry S. haematobium, S. bovis, or possibly S. haematobium x S. bovis hybrid parasites.

-Strengths

The analysis methods (MALDI-TOF MS and PCR sequencing) increase the confidence that snail specimens represent B. forskalii, not B. senegalensis, and that these B. forskalii snails are carrying S. haematobium parasites.

-Weaknesses

Field sampling included a single region in Senegal during a limited temporal window in September 2020. Sampling of more regions over a larger temporal period would increase the confidence that B. forskalii, under a broader range of conditions and environments, can carry S. haematobium infection.

Reviewer #3: The authors' finding is important for the field of Schistosomiasis, particularly in endemic areas because they show definitively that Bu forskalli can host Sh. This finding will be of interest to parasitologists and malacologists; not only for the technology used to draw the study's conclusions, but also because of the implications for human infection. My "major revision" recommendation is mainly to address deficiencies in the Methods section, but does not necessarily require new experiments.

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

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Reviewer #1: No

Reviewer #2: Yes: Kenji Ishida

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, 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

Dear Stephane Ranque,

Thank you for submitting your revised manuscript. The revised version has been backed to assess by expertise reviewers. The revised manuscript have great improvement to clarify the information in materials and methods, statistic used and others. However, there is still minor comments/suggestion to clarify the number of specimens used, especially in table 3 and discuss in depth for the advantage of MADOI-TOF-MS method rather than morphology identification.

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,

Wannaporn Ittiprasert, Ph.D

Academic Editor

PLOS Neglected Tropical Diseases

Makedonka Mitreva

Section 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: Sentence lines 160-162 is duplicated on lines 163-166. (manuscript with track changes)

Table 1 consider change it to Supplementary data.

Reviewer #2: (No Response)

Reviewer #4: The objetives are clearly articulated with a clear testable hypothesis stated

Sample size is somewhat small. This limits the statistical analysis.

Reviewer #5: 1- Line 100: Fig1 could not be downloaded in high resolution

2- Line 115: Please add the genomic coordinates of the area in which the snails were sampled

3- Line 119: Please make it clear which morphological features of the Bulinus forskalii snail species were analyzed

4- Line 145: sentence is duplicated, needs correction

5- Table 1 needs correction: some terms are truncated (Ethanol absolu) or incorrect (Coordonates), etc

6- Line 180: please specify what has been used as negative and positive controls

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

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: Line 264 change paratised to parasitized. (manuscript with track changes)

Why on table 3 do you only have 10 specimens identified on the table? On lines 259 - 260 you indicate that 13 were positives through shedding and 17 through RT-PCR.

Reviewer #2: (No Response)

Reviewer #4: (No Response)

Reviewer #5: The quality of the figures should be improved.

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

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: Line 283 change paratised to parasitized. (manuscript with track changes)

Reviewer #2: (No Response)

Reviewer #4: (No Response)

Reviewer #5: Line 250: Has the authors tried/identified sporocystes in the collected Bulinus forskalii snails?

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

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: (No Response)

Reviewer #2: (No Response)

Reviewer #4: (No Response)

Reviewer #5: (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: I suggested minor revision just to adjust some details and regarding the Table 3 that I still didn’t understand why only consider 10 specimens to add on the table 3.

Reviewer #2: The authors have adequately addressed the reviewers' comments and have improved the quality of the manuscript in this revision. The manuscript is suitable for publication.

Reviewer #4: The paper presented by Mouhamadou et al, entitled Identification of Bulinus forskalii as a potential intermediate host of

Schistosoma haematobium in Senegal, describes a field study for the collection and identification of B. foskalii snails for infection with S. haematobium and S. bovis in an area of the Senegal River during the month of September 2020.

The finding that B. forskalli snails may be intermediate hosts of S. haematobiun is of great interest for the control of schistosomiasis in Sengegal.

The manuscript is well written and structured and allows a good understanding.

Methodologically it is correct, but I would like the authors to discuss in more depth the advantages of the MADI-TOF MS technique for the identification of snails, taking into account that they have previously been identified without problems by morphological characters. They comment in the introduction that morphological identification requires a great deal of expertise, that DNA identification is time-consuming and that there is not much information in databases. In schistosomiasis endemic areas, is it feasible to make a MALDITOF ? It also requires knowledge and experience to do it, as well as the databases to make a good comparison of identifications. Please try to explain this in more detail. Maybe there are not so many advantages compared to an identification of snails by morphology.

Typo in Line 188; S. bovis should be written in italics.

Reviewer #5: The authors provide a report that is centered around the identification/description of Bulinus forskalii snails that can host S. hæmatobium in a limited region of the Senegal River. The manuscript has been greatly improved after the first revision: the descriptions are clearer, the results better presented now, and additional discussions improved the interpretations. I have two main concerns:

1- the fact that a single, limited region in Senegal was sampled in a short temporal window (September 2020). Additional sampling in other regions over a larger period could strengthen the authors’ claim.

2- a demonstration that Bulinus forskalii can be infected by S. hæmatobium outside the field, in the laboratory could strengthen the manuscript. Has this been already performed, or is it possible?

Other points that should be considered are below:

Introduction

1- Line 77: Replace “exclude” by “excluded”

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

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: No

Reviewer #2: Yes: Kenji Ishida

Reviewer #4: No

Reviewer #5: 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, 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.

Dear Dr. Stephane Ranque,

We are pleased to inform you that your manuscript 'Identification of Bulinus forskalii as a potential intermediate host of Schistosoma hæmatobium in Senegal' 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,

Wannaporn Ittiprasert, Ph.D

Academic Editor

PLOS Neglected Tropical Diseases

Makedonka Mitreva

Section 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: (No Response)

Reviewer #4: (No Response)

Reviewer #5: (No Response)

**********

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: (No Response)

Reviewer #4: (No Response)

Reviewer #5: (No Response)

**********

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: (No Response)

Reviewer #4: (No Response)

Reviewer #5: (No Response)

**********

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: (No Response)

Reviewer #4: (No Response)

Reviewer #5: (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: My recommendation is the acceptance of the manuscript since all the suggestions and modifications of reviewers were properly addressed by the authors, and the quality of figures, and manuscript text were also improved. I'm adding my final suggestions to the authors so they can add some modifications before publishing the paper.

AUTHOR SUMMARY

Line 52 (manuscript with track changes): change “characterise” to characterize.

INTRODUCTION

Line 81: change “Bulinid” to Bulinus.

Also, check on the manuscript text where to write Bulinus or just B.

METHODS

Line 127: change “The” to the.

Line 129: the coordinates are 15°30W, as is written on the text, or 15°42W as is written on the S1 table?

Line 131: change “analysed” to analyzed.

On the cercarial shedding test, add the Schistosoma morphological identification, if you performed it.

Did you have any documentation approval, from the Senegal government, to do the snail collection? Can you please add it?

DISCUSSION

Line 317: change “economising” to economizing.

Reviewer #4: (No Response)

Reviewer #5: (No Response)

**********

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: No

Reviewer #4: No

Reviewer #5: No