Identification of Mycobacterium chelonae from Lined Seahorse Hippocampus erectus and Histopathological Analysis

Round 1

Reviewer 1 Report

The MS is reasonably well written. I have only some questions from reading the MS.

I do not understand it. Why did you intentionally contaminate healthy seahorses in your methods, but do not describe it in the Abstract? The Abstract suggests that the purpose of this technical paper was to identify the disease that caused so much mortality in cultured seahorses in China. So, if this procedure helped you reach the conclusion of the study, it should be mentioned in the Abstract.

 

Can't the authors many any comment on why so many diseases strike coastal waters around the globe, especially near or at intensive aquaculture facilities?

 

What does it mean in practical terms, to say these animals are protected?

And is this helping the conservation? What are the actions?

If people do not fish them so often, and culture them, what is the help if intensive farms spread diseases, and humans cause habitat destruction and stocks depletion around the globe? What to do with this information?

Fig 2: Plate is confusing. It is hard to see the differences with respect to controls. Panels A, E, J are said to mean controls for each tissue, but the images of the diseased tissues should be placed next to their controls, for proper visualization of the differences. 

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript submitted by Bai et al., presents a an interesting study on first report of Mycobacterium chelonae releted to outbreaks in Chinease aquaculture. 

Below are some comments that in my opinion may help improve the reception of the article for the audience.

Abstract:

Line 14: an epizootics (plural) were observed

Introduction:

Line 43 Uronema ( sp? spp? genus? italics?)

Line45-47: Please describe the outbreaks in more detail. Two different farms, but are there connections between them, e.g. by water? What's the distance between them, maybe a map would be useful. What were the environmental conditions on the farms? Temperature of water or other data? Where did the stocking material come from? Daily and cumulative mortality are reported, but the duration of the outbreak is not specified. This is a very important issue for the epizootic investigation. Since the authors themselves define this outbreak as an epizootic, they should also treat it from this side in the discussion.

Material and methods:

Line 54-57: Have pathogens other than Mycobacterium spp been tested in diseased fish? Other bacteria, viruses, parasites? Please describe it in more detail.

Line 92-94:

Please describe whether healthy fish intended for infections were tested for pathogens other than Mycobaterium using the nested PCR method?e.g. bacteriological or parasitological tests?

Figure 2.

In line 237 of the discussion, the authors mentioned ovarian lesions that may be important for the reproduction of the species. Are there histological slides of healthy organs for comparision?

How important is ovarian degeneration? How many percent of individuals have these degenerations? How much of the ovary is destroyed, half, a quarter...

How long is the development time of these lesions, how many days after infection the selected slides were taken? Please describe better the clinical changes that occurred.

Figure 3. Enlarge! Please write what method was chosen when constructing the tree and estimating (bootstrap)? Cite appropriate methods or software in References.

Are these isolates included in the phylogenetic analysis automatically selected (Blast) or is there anything known about them? They come from, for example, similar disease episodes on fish farms, what countries are these isolates from? Whether they are isolates from the cases mentioned in the Discussion in lines 211-215 or 187-188? If yes, please indicate which ones? If not, why they are not included?

Please make a list of Genbank numbers used in the analysis and indicate the species from which they were isolated.

Line 237-238: Please expand the topic about the impact of infection on reproduction. This appears to be important for farming and aquaculture.

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf