Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in Dromedary Camels in Africa and Middle East
, Ahmed E. Kayed 1, Jamal S. M. Sabir 2,3, Awatef Abiadh 4, Jamel Jrijer 4, Zuhair Amr 5, Mounir Abi Said 6, Denis K. Byarugaba 7, Fred Wabwire-Mangen 7, Titus Tugume 7, Nadira S. Mohamed 8, Roba Attar 9, Sabah M. Hassan 9,10,11, Sabah Abdulaziz Linjawi 12, Yassmin Moatassim 1, Omnia Kutkat 1, Sara Mahmoud 1, Rabeh El-Shesheny 1,13, Ahmed Mostafa 1, Mohamed A. Ali 1,2,3,* and add
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Round 1
Reviewer 1 Report
The paper is a generally well-written addition to the story of camels, MERS-CoV and MERS. It is disappointing that the very obvious opportunity to sample urine, milk and faeces for the presence of viruses was not taken in this large camel study. As the authors rather quietly and correctly point out (ln83), there are risks attached to the handling and consumption of these camel products that have yet to be suitably studied. This oversight does not impact on the quality of the content presented, however, although its omission as a limitation in the discussion is glaring.
ln40. "and a phylogenetic tree..."
ln52 "..widespread distribution of.."?
ln52-53. Please re-word "A systematic active surveillance" to be more descriptive. It currently is not clear what this phrase would entail. Also repeated at ln347. Also, is this all for use "in humans". Please clarify.
ln75. Was it lack of surveillance, or absence of knowledge of the virus until relatively recently? Please clarify.
ln76. "disease acquired" would be better described as identified or reported.
ln81. "...use of personal protective.."
ln342. What is the seasonal effect the authors hint at? Please elaborate on this.
ln346. "..widespread nature of the virus..."
Author Response
Review Report Form (1)
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English language and style
( ) Extensive editing of English language and style required
( ) Moderate English changes required
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Does the introduction provide sufficient background and include all relevant references? |
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Is the research design appropriate? |
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Are the methods adequately described? |
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Are the results clearly presented? |
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Are the conclusions supported by the results? |
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Comments and Suggestions for Authors
The paper is a generally well-written addition to the story of camels, MERS-CoV and MERS.
It is disappointing that the very obvious opportunity to sample urine, milk and faeces for the presence of viruses was not taken in this large camel study. As the authors rather quietly and correctly point out (ln83), there are risks attached to the handling and consumption of these camel products that have yet to be suitably studied. This oversight does not impact on the quality of the content presented, however, although its omission as a limitation in the discussion is glaring
Added in the limitation section.
ln40. "and a phylogenetic tree..."
Corrected
ln52 "..widespread distribution of.."?
Modified
ln52-53. Please re-word "A systematic active surveillance" to be more descriptive. It currently is not clear what this phrase would entail. Also repeated at ln347. Also, is this all for use "in humans". Please clarify.
Clarified
ln75. Was it lack of surveillance, or absence of knowledge of the virus until relatively recently? Please clarify. ln76. "disease acquired" would be better described as identified or reported.
Modified
ln81. "...use of personal protective.."
Changed
ln342. What is the seasonal effect the authors hint at? Please elaborate on this.
Changed
ln346. "..widespread nature of the virus..."
Changed
Submission Date
09 July 2019
Date of this review
25 Jul 2019 04:41:07
Reviewer 2 Report
This submission provides valuable information on the prevalence of MERS-CoV in dromedary camels. A positive feature of the submission is with its thorough analyses, notably the evaluation of nearly 8000 camel nasal swabs and serum samples for MERS-CoV RNA and neutralizing antibodies. The data are presented adequately, although statistical analyses should be included in figures and tables if possible. The conclusions are, for the most part, supported by the findings.
Specific comments:
Include results of statistical analyses in the figures and tables, if possible.
Include additional description of the phylogenetic tree in Fig. 3. From what length of sequenced fragment was the tree constructed? What was the extent of polymorphism in the sequenced fragment? Is the tree distinct from those trees constructed on the basis of polymorphisms in the ORF1A or N genes that were PCR amplified and sequenced? It was noted on line 330 that previous phylogenetic trees may have been affected because they were based on short sequenced fragments. What makes the tree in Fig. 3 better?
The authors suggest that virus present in seropositive animals is coming from reinfections. If so, then the reinfecting viruses may be variants, for example, antibody escape variants. Do the sequences of the presumed reinfecting viruses separate into a separate group (ie., clade) on the basis of phylogenetic analyses?
Amongst the most interesting statements in the paper is on line 76, "there is no zoonotic MERS disease acquired in Africa". The results in the paper show high seroprevalence as well as recoverable MERS-CoV RNA in African samples. In my opinion, the authors are entitled to speculate (in the discussion) on this conundrum posed by high virus loads in Africa without zoonotic transmission.
Several grammatical corrections must be made to improve the accuracy and flow of the text.
Author Response
Review Report Form (2)
Open Review
(x) I would not like to sign my review report
( ) I would like to sign my review report
English language and style
( ) Extensive editing of English language and style required
(x) Moderate English changes required
( ) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style
|
Yes |
Can be improved |
Must be improved |
Not applicable |
|
|
Does the introduction provide sufficient background and include all relevant references? |
(x) |
( ) |
( ) |
( ) |
|
Is the research design appropriate? |
( ) |
(x) |
( ) |
( ) |
|
Are the methods adequately described? |
( ) |
(x) |
( ) |
( ) |
|
Are the results clearly presented? |
(x) |
( ) |
( ) |
( ) |
|
Are the conclusions supported by the results? |
( ) |
(x) |
( ) |
( ) |
Comments and Suggestions for Authors
This submission provides valuable information on the prevalence of MERS-CoV in dromedary camels. A positive feature of the submission is with its thorough analyses, notably the evaluation of nearly 8000 camel nasal swabs and serum samples for MERS-CoV RNA and neutralizing antibodies. The data are presented adequately, although statistical analyses should be included in figures and tables if possible. The conclusions are, for the most part, supported by the findings.
Specific comments:
Include results of statistical analyses in the figures and tables, if possible.
Include additional description of the phylogenetic tree in Fig. 3. From what length of sequenced fragment was the tree constructed? What was the extent of polymorphism in the sequenced fragment? Is the tree distinct from those trees constructed on the basis of polymorphisms in the ORF1A or N genes that were PCR amplified and sequenced? It was noted on line 330 that previous phylogenetic trees may have been affected because they were based on short sequenced fragments. What makes the tree in Fig. 3 better?
The length of amplicons and rational of the tree was added in the results and figure ligand as suggested
The authors suggest that virus present in seropositive animals is coming from reinfections. If so, then the reinfecting viruses may be variants, for example, antibody escape variants. Do the sequences of the presumed reinfecting viruses separate into a separate group (ie., clade) on the basis of phylogenetic analyses?
Our group and other showed the reinfections of seropositive camels are common.
Amongst the most interesting statements in the paper is on line 76, "there is no zoonotic MERS disease acquired in Africa". The results in the paper show high seroprevalence as well as recoverable MERS-CoV RNA in African samples. In my opinion, the authors are entitled to speculate (in the discussion) on this conundrum posed by high virus loads in Africa without zoonotic transmission.
Added in the discussion
Several grammatical corrections must be made to improve the accuracy and flow of the text.
