Prevalence of mastitis and its associated risk factors in lactating camels in Northern Egypt

Abdelfattah Selim; Mohamed Marzok; Hattan S. Gattan; Hesham Ismail

doi:10.1371/journal.pone.0333826

Peer Review History

Original SubmissionJune 13, 2025
29 Jul 2025 Decision Letter - Pierre Germon, Editor Dear Dr. Selim, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Although both reviewers found interest in your study, they raised a number of concerns that need to be adressed. In particular, both reviewers asked for more details regarding reporting of prevalence of clinical and subclinical mastitis at both the camel level and the quarter level separately. Please submit your revised manuscript by Sep 12 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . 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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: Yes Reviewer #2: No ******** 2. Has the statistical analysis been performed appropriately and rigorously? -->?> Reviewer #1: Yes Reviewer #2: Yes ****** 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 research article, titled "Prevalence of Mastitis and Its Associated Risk Factors in Lactating Camels in Northern Egypt," published in PLOS ONE, presents a cross-sectional epidemiological investigation into camel mastitis across three governorates: Kafr El-Sheikh, Qalyubia, and Menofia. The study assessed 390 lactating camels using the California Mastitis Test (CMT) and identified both clinical and subclinical cases. The overall prevalence was 38.46%, with clinical mastitis accounting for 6.4% and subclinical mastitis for 32.1% of the examined animals. Multivariable logistic regression identified several significant risk factors: camels older than five years were 6.2 times more likely to be affected; early lactation stage increased risk by 2.5 times; tick infestation (OR=1.5), poor milking hygiene (OR=2.4), and the presence of udder or teat lesions (OR=2.5) were also strongly associated with higher mastitis prevalence. In contrast, locality and body condition score showed no significant association. The study’s methodology included clinical examination, milk sampling, and structured questionnaires, with statistical analyses performed using SPSS. The authors emphasize the economic and public health burden of subclinical mastitis, which frequently escapes detection, and advocate for improved management practices, including hygiene protocols and tick control measures. The study received ethical approval from Benha University, declares no funding or competing interests, and confirms that data are available upon reasonable request. Overall, this research provides important epidemiological data that can inform targeted interventions to improve udder health and milk safety in Egyptian camel populations. Review Comments and Suggestions • Kindly present the prevalence of clinical and subclinical mastitis at both the camel level and the quarter level separately. • Table 2:The title of column 2 suggests that dogs were sampled - kindly correct this. • Line 158: Kindly italicise Camelus dromedarius. Reviewer #2: The test/criteria for diagnosis of sub-clinical and clinical mastitis applied in the study is not adequate to get an authentic result. Furthermore, it is not clear that prevalence is quarterwise or animal wise. ****** 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". 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Revision 1
7 Aug 2025 Author Response Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: No ________________________________________ 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ________________________________________ 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ________________________________________ 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ________________________________________ 5. Review Comments to the Author This research article, titled "Prevalence of Mastitis and Its Associated Risk Factors in Lactating Camels in Northern Egypt," published in PLOS ONE, presents a cross-sectional epidemiological investigation into camel mastitis across three governorates: Kafr El-Sheikh, Qalyubia, and Menofia. The study assessed 390 lactating camels using the California Mastitis Test (CMT) and identified both clinical and subclinical cases. The overall prevalence was 38.46%, with clinical mastitis accounting for 6.4% and subclinical mastitis for 32.1% of the examined animals. Multivariable logistic regression identified several significant risk factors: camels older than five years were 6.2 times more likely to be affected; early lactation stage increased risk by 2.5 times; tick infestation (OR=1.5), poor milking hygiene (OR=2.4), and the presence of udder or teat lesions (OR=2.5) were also strongly associated with higher mastitis prevalence. In contrast, locality and body condition score showed no significant association. The study’s methodology included clinical examination, milk sampling, and structured questionnaires, with statistical analyses performed using SPSS. The authors emphasize the economic and public health burden of subclinical mastitis, which frequently escapes detection, and advocate for improved management practices, including hygiene protocols and tick control measures. The study received ethical approval from Benha University, declares no funding or competing interests, and confirms that data are available upon reasonable request. Overall, this research provides important epidemiological data that can inform targeted interventions to improve udder health and milk safety in Egyptian camel populations. Review Comments and Suggestions Point#: Kindly present the prevalence of clinical and subclinical mastitis at both the camel level and the quarter level separately. Response# it was clarified Point#: Table 2:The title of column 2 suggests that dogs were sampled - kindly correct this. Response# it corrected Point#: Line 158: Kindly italicise Camelus dromedarius. Response# it edited Reviewer 2: Comments on the manuscript entitled “Prevalence of Mastitis and Its Associated Risk Factors in Lactating Camels in Northern Egypt” General Comments This is an informative study, revealing various risk factors for sub-clinical and clinical mastitis in camel. However, a significant weakness is the use of CMT as sole tool for mastitis diagnosis Point#: For accurate and sensitive subclinical mastitis diagnosis, use of somatic cell count and/or isolation of pathogenic bacteria from milk are also suggested to include. The manuscript is well written and statistical analysis is also appropriate. Materials & Methods Point#: The sub-clinical and clinical mastitis in camel was diagnosed using CMT that was originally developed for use in cattle. Though an old technique, it still serves as backbone of mastitis diagnosis. However, several paper has suggested certain modifications for improving diagnostic sensitivity and specificity in camel, as chemical properties of normal as well as mastitic camel milk differ from those in cattle. Authors should describe in detail the scoring system. I am unable to conclude what is 3% CMT reagent? Point#: Furthermore, I am unable to decide whether the prevalence is calculated as animal basis or udder-quarter basis. The authors should clarify how many quarters were examined and how much were found positive for mastitis? Results should be presented as both quarter wise and animal wise prevalence. Response#: it was clarified and added Point#: Criteria for body condition scoring is not described. Response#: it added Specific Comments Point#: Line No. 39: Revise the sentence “It also contains higher phosphorus levels than other cattle”. Response#: it deleted Attachments Attachment Submitted filename: Response to reveiewe comments.doc https://doi.org/10.1371/journal.pone.0333826.r002
19 Aug 2025 Decision Letter - Pierre Germon, Editor Dear Dr. Selim, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. In particular, I consider that you have only partially adressed the comments made by both reviewers on the original submission. 1- Table1 and table 2 are somewhat duplicated and should be compiled into a single table. In such a table, you should indicate one column for « No of positive camels ^a », with its associated « Camel-level prevalence %» column, and a one column for « No of positive quarter samples ^b » and a « Quarter-level prevalence % » column. Subscripts a and b should indicate the total number of camels and quarters respectively as a footnote of the table. 2- In table 5, you should specify the distribution between clinical and subclinical cases. For instance, for each pathogen, you could mention in parenthesis the number of clinical and subclinical cases from which this pathogen was identified. If, as an example, among the 95 E. coli isolates 20 are from subclinical casees, you could indicate 95 (20/75). 3- Furthermore, you should clarify how you selected the 600 milk samples for bacteriological analysis since you only observed 450 mastitic quarters. For this last comment, I insist that you not only correct the manuscript file but also give details in your response to this comments. You will have to adjust the abstract. Please submit your revised manuscript by Oct 03 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. 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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. [Note: HTML markup is below. Please do not edit.] [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.] 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. Registration is free. 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 PLOS at figures@plos.org . Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0333826.r003
Revision 2
1 Sep 2025 Author Response Point#: Table1 and table 2 are somewhat duplicated and should be compiled into a single table. In such a table, you should indicate one column for « No of positive camels a», with its associated « Camel-level prevalence %» column, and a one column for « No of positive quarter samples b» and a « Quarter-level prevalence % » column. Subscripts a and b should indicate the total number of camels and quarters respectively as a footnote of the table. Response#: both tables were merged Point#: In table 5, you should specify the distribution between clinical and subclinical cases. For instance, for each pathogen, you could mention in parenthesis the number of clinical and subclinical cases from which this pathogen was identified. If, as an example, among the 95 E. coli isolates 20 are from subclinical casees, you could indicate 95 (20/75). Response#: it rephrased Point#: Furthermore, you should clarify how you selected the 600 milk samples for bacteriological analysis since you only observed 450 mastitic quarters. For this last comment, I insist that you not only correct the manuscript file but also give details in your response to this comments. You will have to adjust the abstract. Response#: The results revealed that 150 animals tested positive. From these animals, 600 milk samples representing their quarters were subjected to bacteriological examination. Attachments Attachment Submitted filename: response to reviewer comments.doc https://doi.org/10.1371/journal.pone.0333826.r004
18 Sep 2025 Decision Letter - Pierre Germon, Editor Prevalence of Mastitis and Its Associated Risk Factors in Lactating Camels in Northern Egypt PONE-D-25-32223R2 Dear Dr. Selim, 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, Pierre Germon Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0333826.r005
Formally Accepted
Acceptance Letter - Pierre Germon, Editor PONE-D-25-32223R2 PLOS ONE Dear Dr. Selim, 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 Dr. Pierre Germon Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0333826.r006

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