Serological evidence of West Nile virus circulation in Indonesia: Initial insights into an underrecognized flavivirus threat

Yora Permata Dewi; Rintis Noviyanti; Leily Trianty; Enny Kenangalem; Frilasita Aisyah Yudhaputri; Matthew J. Grigg; Jeremy P. Ledermann; Ann M. Powers; Eric C. Mossel; Khin Saw Aye Myint

doi:10.1371/journal.pone.0342511

Peer Review History

Original SubmissionOctober 9, 2025
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If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? Reviewer #1: Partly Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? -->?> Reviewer #1: N/A Reviewer #2: No ****** 3. Have the authors made all data underlying the findings in their manuscript fully available??> The PLOS Data policy Reviewer #1: Yes Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English??> Reviewer #1: Yes Reviewer #2: Yes ****** Reviewer #1: This paper provided evidence of West Nile Virus IgM positivity among people in Kalimantan and Papua. Unfortunately, there are some points that should be addressed to improve the paper quality. Comments Methods: Fourth paragraph, line 102 – 104: Add the reference for the reported sensitivity and specificity for the test. Fourth paragraph, line 108 – 109: Add more information on how to decide the final serostatus. Results: Table 1: The numbers for N in Nunukan and Malinau sites were not matched with the numbers for sex and age group. Check again the numbers. Table 2: The notes under the table should be added in the Methods section and in more detail. Discussion: Line 173 – 183 : Are there any references for this paragraph? Last paragraph, line 191 – 193: “The modest sample size limits statistical power…” This study did not have “modest sample size”, it had “very small number of positive cases”. The authors did not mention anything about wanted to prove something by statistical test. Hence, it is quite confusing why suddenly the statistical power was mentioned as study limitation. With two positive cases, it was no longer “reduces the ability to detect regional patterns”. The authors did not have the ability to detect regional patterns. Reviewer #2: This is a well written and valuable study that provides updated serologic data on WNV exposure in a population often underrepresented in surveillance. The findings are timely and contribute to understanding possible WNV circulation in Indonesia. For future, inclusion of IgG testing and addition of negative serum tested for JEV sero-complexes could strengthen the assessment and make the study’s design and analysis more robust and informative. Introduction Line 60 – to be more precise and use commonly used term in current literature, acute flaccid myelitis Line 61- to be more specific, the surveillance in humans only or including mosquitoes Line 74- It was stated to investigate recent infection, but some of the samples were old sample from 3 years ago, the word recent infection is not suitable. It is understandable your focus in on non-febrile patient, therefore this sentence needs to be rephrased. Line 75 – specify the general population location Line 76- state the study focuses on non-febrile patient. Methodology Line 104 - state what type of ELISA. How the cut-off value of ISR is determined for both ELISA (WNV IgM and CDC MAC -ELISA)? The result is an OD or concentration of antibody? Line 108 - where did you perform the CDC MAC-ELISA protocol? State possible reason why IgG based ELISA and RT-PCR was not included in this study? Add statistical analysis. Discussion While previous studies shown that WNV IgM can persist and sometimes indicate exposure, its duration is variable and less predictable in mild or asymptomatic infections. For more robust evidence of prior or cumulative exposure, including an IgG-based ELISA is recommended, ideally alongside IgM to distinguish recent versus past infection. Also how to confirm that the infection is recent if IgM-based ELISA could indicate both recent and exposure based on the study objective ( Line 74). Have you considered screening serum samples from febrile patients that tested negative for dengue, Zika and JE? This could be a valuable approach for future studies. ****** 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: No ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] To ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation. NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications. Attachments Attachment Submitted filename: comment to author.docx https://doi.org/10.1371/journal.pone.0342511.r001
Revision 1
9 Jan 2026 Author Response Reviewer #1: This paper provided evidence of West Nile Virus IgM positivity among people in Kalimantan and Papua. Unfortunately, there are some points that should be addressed to improve the paper quality. RESPONSE: We appreciate the reviewer’s constructive comments highlighting important issues and have revised accordingly, as detailed below. Comments Methods: Fourth paragraph, line 102 – 104: Add the reference for the reported sensitivity and specificity for the test. RESPONSE: A reference was added to reflect the revision. Fourth paragraph, line 108 – 109: Add more information on how to decide the final serostatus. RESPONSE: We appreciate the reviewer’s suggestion and have added a detailed explanation of how final serostatus was determined. These definitions are now included in the Methods section (Lines 121-126). Results: Table 1: The numbers for N in Nunukan and Malinau sites were not matched with the numbers for sex and age group. Check again the numbers. RESPONSE: We thank the reviewer for spotting this typographical error. The values have been corrected. Table 2: The notes under the table should be added in the Methods section and in more detail. RESPONSE: It has now been integrated into the Methods section for clarity. Discussion: Line 173 – 183: Are there any references for this paragraph? RESPONSE: Relevant reference has now been added to support this section. Last paragraph, line 191 – 193: “The modest sample size limits statistical power…” This study did not have “modest sample size”, it had “very small number of positive cases”. The authors did not mention anything about wanted to prove something by statistical test. Hence, it is quite confusing why suddenly the statistical power was mentioned as study limitation. With two positive cases, it was no longer “reduces the ability to detect regional patterns”. The authors did not have the ability to detect regional patterns. RESPONSE: We thank the reviewer for this comment and agree that the original wording overstated our ability to perform statistical analyses. We have made the necessary correction (Lines 233-234). Reviewer #2: This is a well written and valuable study that provides updated serologic data on WNV exposure in a population often underrepresented in surveillance. The findings are timely and contribute to understanding possible WNV circulation in Indonesia. For future, inclusion of IgG testing and addition of negative serum tested for JEV sero-complexes could strengthen the assessment and make the study’s design and analysis more robust and informative. RESPONSE: We thank Reviewer 2 for the positive comments. Introduction Line 60 – to be more precise and use commonly used term in current literature, acute flaccid myelitis RESPONSE: The term has been revised to acute flaccid myelitis. Line 61- to be more specific, the surveillance in humans only or including mosquitoes RESPONSE: The sentence has been revised to “The high frequency of inapparent infections in humans complicates surveillance efforts and contributes to substantial underreporting.” Line 74- It was stated to investigate recent infection, but some of the samples were old sample from 3 years ago, the word recent infection is not suitable. It is understandable your focus in on non-febrile patient, therefore this sentence needs to be rephrased. RESPONSE: We have revised the statement to “This study aimed to investigate the presence of WNV infections among non-febrile individuals.” Line 75 – specify the general population location RESPONSE: This has been added (Line 78). The detailed location of the general population sampled is described in the Methods section (Paragraph 1). Line 76- state the study focuses on non-febrile patient. RESPONSE: This has been clarified in the revised text. Methodology Line 104 - state what type of ELISA. How the cut-off value of ISR is determined for both ELISA (WNV IgM and CDC MAC -ELISA)? The result is an OD or concentration of antibody? RESPONSE: We have revised the Methods section to specify the type of ELISA used and to explain how the cut-off values for both the InBios WNV IgM ELISA and the CDC MAC-ELISA were determined (Lines 107-129). Line 108 - where did you perform the CDC MAC-ELISA protocol? State possible reason why IgG based ELISA and RT-PCR was not included in this study? Add statistical analysis. RESPONSE: All laboratory assays, including the CDC MAC-ELISA, were performed at our laboratory at the Exeins Health Initiative (EHI), Indonesia. IgG ELISA and RT-PCR were not included in this study due to the study’s focus on detecting IgM responses in non-febrile individuals rather than assessing long-term immunity (IgG) or active viremia (RT-PCR), combined with the limited diagnostic yield expected from the available specimens and budgetary constraints that precluded additional testing. Statistical analysis has now been added in Lines 131-140. Discussion While previous studies shown that WNV IgM can persist and sometimes indicate exposure, its duration is variable and less predictable in mild or asymptomatic infections. For more robust evidence of prior or cumulative exposure, including an IgG-based ELISA is recommended, ideally alongside IgM to distinguish recent versus past infection. Also how to confirm that the infection is recent if IgM-based ELISA could indicate both recent and exposure based on the study objective (Line 75-76). RESPONSE: We thank the reviewer for this important clarification. In the revised Discussion, we clarify that determining truly recent WNV infection was not possible in this study because only single serum samples were available (Lines 224-228). We also agree that IgG-based ELISA, ideally interpreted together with IgM, would provide more robust evidence of cumulative or past exposure and help distinguish recent from historic infection. However, IgG testing was not included in the present study due to resource and logistical constraints, and we now explicitly acknowledge this as a limitation (Lines 230-233). We have revised the study objective and related text (Line 75) to avoid implying that IgM alone can confirm recent infection. The updated wording now states that the study aimed to investigate the presence of WNV infections among non-febrile individuals (Lines 75-76), rather than strictly “recent” infections. Confirming recent infection would require additional diagnostic approaches such as demonstrating IgG seroconversion using paired acute and convalescent sera. These methods were beyond the scope of the current study and were not feasible given the available samples. This clarification ensures that the interpretation of IgM results remains accurate and does not overstate what IgM-based ELISA can determine. Have you considered screening serum samples from febrile patients that tested negative for dengue, Zika and JE? This could be a valuable approach for future studies. RESPONSE: This approach was not feasible for the present study, which focused exclusively on non-febrile individuals, and access to febrile samples fell outside the project scope. We have added this as a recommendation for future studies. Attachments Attachment Submitted filename: Response to Reviewers_Rev1 05012026.docx https://doi.org/10.1371/journal.pone.0342511.r002
26 Jan 2026 Decision Letter - Mirko Cortese, Editor Serological evidence of West Nile virus circulation in Indonesia: Initial insights into an underrecognized flavivirus threat PONE-D-25-54301R1 Dear Dr. Myint, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support . If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Mirko Cortese Academic Editor PLOS One https://doi.org/10.1371/journal.pone.0342511.r003
Formally Accepted
Acceptance Letter - Mirko Cortese, Editor PONE-D-25-54301R1 PLOS One Dear Dr. Myint, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS One. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. You will receive an invoice from PLOS for your publication fee after your manuscript has reached the completed accept phase. If you receive an email requesting payment before acceptance or for any other service, this may be a phishing scheme. Learn how to identify phishing emails and protect your accounts at https://explore.plos.org/phishing. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Prof. Mirko Cortese Academic Editor PLOS One https://doi.org/10.1371/journal.pone.0342511.r004

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