The Prevalence and Determinants of Taenia multiceps Infection (Cerebral Coenurosis) in Small Ruminants in Africa: A Systematic Review

Round 1

Reviewer 1 Report

Authors compile a group of 11 research papers in order to review the prevalence and determinants of Coenurus cerebralis in small ruminants in Africa.

Although the idea of showing overall data about the diseases, authors should take into consideration serveral important points to improve the review.

Coenurosis is a parasitic diseases caused by the larval stage (Coenurus cerebralis) of the adult flatworm Taenia multiceps. Since this is the main cause and the core of the systemic review, authors should name the larval stage (C. cerebralis) instead of making reference to Taenia multiceps, as this parasite is only presence in the definitive host (dog) and it could cause confusion.

Regarding the number of articles included in the systematic review, authors start from a number of 574 records that were reduced to 11 studies. These figures seems to be low for such a huge continent and an important parasitic disease as coenurosis. There should be a way to include more articles if possible to make the review more complete.

In Materials and Methods section, a protocol from CADIMA is mentioned but there are no details and the authors should draft this protocol in brief for those readers who have never done a systematic review.

Other corrections.

1. The Font for the PRISMA flow chart has to be homogenised.
2. Line 125: “Out of the eleven studies”.
3. Line 128: “Table 1. Prevalence of cerebralis for sheep and goats…”.
4. Line 133: “2.3. Prevalence of cerebralis”. Authors are given prevalence in goats and sheep.
5. Figure 2. Remove word “year” from caption.
6. Line 153: “Determinants of prevalence of cenurosis”.
7. Line 163: feces.
8. Line 170: “This indicating a wide geographic distribution of the disease” can be removed.
9. Line 194: Taenia multiceps.
10. Lines 160, 161, 223, 303 and 306: please double check commas and semicolon.

Author Response

Thank you for your review.  Points/comments have been addressed (attachment). 

Author Response File: Author Response.pdf

Reviewer 2 Report

Authors submitted interesting manuscript presenting accessible knowledge about T. multiceps larval infection in small ruminants in Africa – in the form of systematic review.

Comments:

Systematic review is characterized by objectivity of searching and choosing the papers for review. Moreover this way of making review paper is distingished with transparency. Therefore, some points are strongly needed:

- there is lack of references of 11 studies included to SR (?!) it is the basis. Readars have only shorten descriptions (name, year) in table 1. It has to be added absolutely  to the paper.

- the proces of exclusion is presented in the flow chart – that’s OK. But the proces of excluison/inclusion shuold be transparent, it means that authors have to add also list of excluded papers (full texts) togather with the reason of exclusion. Now, readers do not know why some paper were excluded etc. Such list could be located in supplementary file.

there is some inconsistency in the description of the inclusion / exclusion criteria. (line 271-276). Namely, in point (ii) of inclusion criteria, the author's wrote that articles were included when: "reported risk factors AND / OR prevalence of T. multiceps .." However, in excusion criteria point (ii) authors stated that articles were excluded when "lacked epidemiological data AND risk factors or determinats .... ". So, According to inclusion criteria it is enough when paper contaion only prevalecne OR risk factors (it seems be correct); but according to excluision criteria papers sholud have both: epidemiologucla data AND risk factors – otherwise they will be excluded. (?). I think that there is a mistake in description of point (ii) of exclusion criteria and AND/OR should be put instead of AND.

 It is suggested adding tables S3 and S4 to main text of the manyuscript. They are important and it would be better to have tchem in mian text not only as supplementary data.

Coenurus cerebralis is not a taxonomic species name – it is only latin name of larval stage, it means that it sholuld be lowercase.

Line194 : „T. multiceps”

Author Response

Thank you for your review.  Points/comments have been addressed (attached cover letter). 

Author Response File: Author Response.pdf

Reviewer 3 Report

A concisely written systematic review, which, however, mainly highlights the huge gaps of knowledge on T. multiceps (as with other important livestock parasites) in Africa. Only eleven publications (all except three from Egypt and Ethiopia) from two decades were retrieved as eligible, which brings me to the purpose of the study. As the authors acknowledge, the few eligible studies (with unclear test sensitivities and selection bias) help little to delimit geography and determine risk factors and determinants of prevalence. Would it not be far more useful, after all this effort, to widen the eligibility criteria and provide the reader with a sound reference basis on what we know about T. multiceps in Africa (which is not that much)? That would include records and frequencies in dogs (Mulinge et al., 2020 from Kenya springs to mind) and case series without prevalence figures from other countries in Africa (like in Christodoulopoulos et al., 2016). Based on the latter paper it should also be discussed that T. multiceps does not only form cerebral coenuri, but also metacestodes in the musculature which may or may not have been detected (and searched for) in the cited prevalence studies.

Other comments:

69 – Terminal proglottids of...

83 – becoming

120-126 – the difference between communal and abattoir studies is no self-explanatory and needs some description. Is it meant that smallstock is sold to abattoirs for money, while the communal slaughter is home slaughter for consumption?

194 – Taenia multiceps infection of dogs can be treated...

198-208 – I guess that the most effective method to control dog transmitted livestock parasites is by high standards of slaughterhouses and destruction of offal / inaccessibility to dogs. Dog deworming programmes are expensive, usually unsustainable and require highly developed infrastructure. There is an enormous body of literature on control of echinococcosis, which is basically the same thing (summarized by Craig et al., 2017 Adv Parasitol 96). No need to re-invent the wheel for each taeniid species!

224 – reference 43 is an awful piece of non-science. The authors do not differentiate between Taenia, taeniids, Echinococcus and whatever.

236-242 – I do not understand any of this – please rephrase!

Author Response

Thank you for your review.  Points/comments have been addressed (cover latter attached). 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Thank you for taking into consideration my comments.

Only little additional comment and question:

With reference to review authors add the additional list to Supplementary Materials (“Excluded papers”. So, in manuscript in point “Supplementary materials” (Line 323-330)  authors have to add information that there is also “List of excluded papers” in supplementary files.

I don't understand exactly what is the reason for including the file entitled “Review_protocol_statement” in the additional files. It includes some duplicated (or shortened) information concerning introduction and methodology from main text of manuscript (?). Is it necessary?

Author Response

Thank for for your time and efforts rendered to review our manuscript. Responses to your comments and suggestion are attached. 

Author Response File: Author Response.docx

Reviewer 3 Report

Apart from minor mistakes, none of my suggestions were considered. Still, I see no scientific flaws in the study and it can be published.

Author Response

We appreciate for time and effort rendered to review our manuscript. 

Author Response File: Author Response.pdf