Dear Dr. Srisawat:

Thank you very much for submitting your manuscript "DEVELOPMENT and VALIDATION of a SIMPLE SCORE for DIAGNOSIS of LEPTOSPIROSIS at OUTPATIENT DEPARTMENTS" (#PNTD-D-19-01397) for review by PLOS Neglected Tropical Diseases. Your manuscript was fully evaluated at the editorial level and by independent peer reviewers. The reviewers appreciated the attention to an important problem, but raised some substantial concerns about the manuscript as it currently stands. These issues must be addressed before we would be willing to consider a revised version of your study. We cannot, of course, promise publication at that time.

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Sincerely,

Nicholas P. Day

Associate Editor

PLOS Neglected Tropical Diseases

Mathieu Picardeau

Deputy Editor

PLOS Neglected Tropical Diseases

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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: (No Response)

Reviewer #3: Authors have developed a score used for as a diagnosis tool to identify mild or early phase symptoms of human leptospirosis in rural healthcare units with limited laboratory resources based on data from "cases" and "non-cases" patients in Si Sa Ket, a province in Northeast Thailand, between December 2017 and November 2018.

Most methods were lacking of reference citations for example, all laboratory tests used in the study such as culture, polymerase chain reaction, and MAT methods; cases and non-cases definitions; the method used for sample size estimation; and the modified WHO score used in the study.

Section "Blood sample and specimen collection" is not well described. For example, which kinds of blood tubes were used for culture, PCR and MAT, which parts of blood (or urine) samples were collected after centrifuge and for what tests, centrifugation force was not specified. It is confusing that frozen samples were sent to culture (this definitely need the step-by-step-protocol or reference citation.

For the definition of leptospirosis cases, the first criteria "isolation of Leptospira from clinical specimen" might not accurate. How much do authors be certain if pathogenic Leptospira species isolated from urine samples collected from patients who having 2 days of fever? Or how much author be certain the species or group (pathogens or non-pathogens) of Leptospira isolated from blood or urine specimens.

Clinical outcomes (at least after 7 days, the second visit) and treatments are important for evaluation the success of non-intervention routine practices. However, these data were not collected in this study.

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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: (No Response)

Reviewer #2: (No Response)

Reviewer #3: The results of Leptospira isolations (both blood and urine specimens), PCR and MAT (paired serum) were not presented. These results are keys results for proper "cases" and "non-cases" definitions. Only final number of cases and non-cases were described.

The results of WHO score in each "cases" and "non-cases" groups are important, however, they were not shown.

Table 1 and 3 shows combination of both category parameters and numeric parameters. However, the heading are not specify well.

Is it accurate to use mean (in stead of median and IQR) to compare the OPD score of "cases" and "non-cases" group as shown in Table 6?

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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: (No Response)

Reviewer #2: (No Response)

Reviewer #3: The data shown in the manuscript supported that "the OPD score" is better than the WHO score in the study endemic setting of Si Sa Ket province. However, the discussion on why the WHO score is not successful when used in this setting is not mention (even Laboratory data was available). Is the OPD score is suitable for human leptospirosis with other complication such as respiratory or heart diseases (not only kidney complication). Or is the OPD score is suitable for other endemic area in the Southern of Thailand or Malaysia, where less cattle farms and rice paddy fields but more rubber gardens, forest trekking and stray dogs.

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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: (No Response)

Reviewer #2: (No Response)

Reviewer #3: 1. Revision the "Methods" with all possible reference citations and laboratory brief protocols. And also specify the following details; PCR format (conventional or real-time PCR), target gene (rrs, lipL32 or others), Laboratory institute where all tests performed.

2. Adding PCR, culture and MAT results; and the WHO score results.

3. Improving heading and legend in Table 1 and 3.

4. Using median and IQR instead of mean and SD when it is appropriate.

5. Improving discussion on the limitation of the "OPD score".

6. Checking spelling and grammar for the whole manuscript again. Please correct the "drip stick". It should be "dipstick".

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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: (No Response)

Reviewer #2: Manuscript Review: Development and Validation of a Simple Score for Diagnosis of Leptospirosis at Outpatient Departments

Journal: PLoS NTD

Manuscript ID: PNTD-D-19-01397

This study proposes a scoring system for identifying patients with early leptospirosis. The rationale for the study is that identification of early leptospirosis using a simple set of questions and tests would be broadly applicable and could enable therapy at a stage that could prevent or reduce more severe complications. Although cases of leptospirosis were confirmed by MAT, serologic testing and other leptospirosis-specific tests were not considered as these are not available in many settings.

An OPD score was developed based on five relatively novel and potentially useful criteria. The “wet ground at workplace” criterion is certainly more specific than the Modified Faine’s criterion of “rainfall”. Likewise, contact with an “animal water reservoir” is more specific than “animal contact” or contact with “contaminated environment”. The three laboratory criteria are readily obtainable in many outpatient settings. Although the proposed OPD scoring system could be potentially useful, I have a number of concerns that should be addressed.

Comments:

1. The authors should summarize Faine’s original and modified criteria for readers not familiar with these diagnostic scoring systems.

2. The authors should summarize the sensitivity and specificity of Modified Faine’s Criteria as reported by others (references 24-27) and compare these published results with those reported here.

3. The crude odds ratios for “wet ground at workplace” of 2.83 is not supported by the percentages in confirmed (27.4%) and non-cases (20.2%).

4. How much protein or blood in the urine is required for a positive score for those criteria?

5. The data for patients with neutrophil percentage >80% among confirmed and non-cases is missing.

6. The data for some of the modified Faine’s criteria (such as rainfall) among confirmed and non-cases is missing.

7. What percentage of non-cases were diagnosed with infections other than leptospirosis? What were those alternative diagnoses and how often did they occur?

8. Did any of the leptospirosis patients in this study develop more severe complications including death? How many of the leptospirosis cases in this study were later admitted to the hospital or treated for leptospirosis?

9. What was the average time from onset of symptoms to evaluation?

Reviewer #3: The OPD score is an alternative tool for screening human leptospirosis for rural healthcare units with limited laboratory resources. However, further sensitivity and specificity validations in other endemic (various prevalence) and non-endemic regions should be emphasized.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

Attachments

Attachment

Submitted filename: Review PLoS NTD-PNTD-D-19-01397_TA.docx

Dear Dr. Srisawat,

We are pleased to inform you that your manuscript, "DEVELOPMENT and VALIDATION of a SIMPLE SCORE for DIAGNOSIS of LEPTOSPIROSIS at OUTPATIENT DEPARTMENTS", has been editorially accepted for publication at PLOS Neglected Tropical Diseases.

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

Best regards,

Nicholas P. Day

Associate Editor

PLOS Neglected Tropical Diseases

Mathieu Picardeau

Deputy Editor

PLOS Neglected Tropical Diseases

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