Testing for "fish TB" -pics included
Posted 01 March 2010 - 05:29 PM
I started suspecting fish tuberculosis (which is actually a non-tuberculous mycobacteria, usually M. marinum or M. fortuitum) after reading this article posted on the forum: http://www.atlasbook...mycoarticle.pdf
Then I went on to several other articles, the most useful of which is this: http://edis.ifas.ufl.edu/vm055
Today I went up to my old college to do the stain to find out whether or not my fears of mycobacteriosis were unfounded. My old advisor, Dr Coggin, was kind enough to help me with the process since once I actually got in there I got a little frazzled. I'm not exactly comfortable with cutting open my pets with a scalpel after all.
The fish I chose was one of my female bettas, Ruby. She was quite obviously in bad shape and would not have lasted the week.
The light colored spots are where the light from the hood was shining through her body from the other side.
I euthanized her using clove oil, and put her in a petri dish to get the sample. It was disturbing to say the least. Her body did not have the firm feel that I'm used to when touching fish, but rather felt almost exactly like a water balloon.
I used a scalpel to start the incision to inspect the organs for granulomas (the white balls of tissue that forms around bacteria in the body's attempt to wall it off). Searching proved to be entirely unnecessary, however, because as soon as the scalpel went in, granulomas came out. Unlike the fish in the second article I posted up there, Ruby's body was completely packed full to the extent that it looked as if she was bleeding tapioca. It was so unbelievable that Dr. Coggin had to assure me that it was actually granulomas we were seeing.
I'm just going to post this picture as a link since it's a bit graphic:
And one of a few granulomas separated out:
And on to the test itself, Dr. Coggin took a single granuloma, crushed it, and smeared it on a microscope slide. Then I heat-set it by passing it through the flame of a bunsen burner. After that I added a few drops of Zeihl's Carbolfuchsin stain and put it over steam for 5 minutes to set.
After that I rinsed the stain off with water and then decolorized it with an acid alcohol solution (most bacteria will not hold stain when washed in acid alcohol, but myco is one of the very very few kinds that will).
Next I counterstained with methylene blue for one minute.
After that was rinsed off with water we could finally put it under the scope using an oil-immersion lense (1000x) and see if there was any bacteria showing as red. Unfortunately my camera couldn't get a clear shot, but Dr. Coggin is keeping the slide and will email me some pics if he gets a chance to use the microscope with the built-in camera.
Dr. Coggin confirmed it, it's a definite positive for acid-fast bacteria. My fish do in fact have TB.
Posted 01 March 2010 - 05:40 PM
Are you going to have to euthanize them all now?
Posted 01 March 2010 - 05:43 PM
Posted 01 March 2010 - 06:12 PM
Posted 01 March 2010 - 06:45 PM
Oh my goodness! That's awful.
Are you going to have to euthanize them all now?
Any that I can't find homes for. Even if it was just up to me I'd want that bacteria out of my house, and there's no way my parents would put up with it.
Sorry to hear that this was the outcome. I am going to PM you.
Oh yuck sorry about your fish and good luck sterilising the equipment. But thanks for the post, it really helped me understand the disease better, what to look for and why its there.
I'm glad this whole thing can at least be helpful to other people.
Posted 18 March 2010 - 09:16 PM
TB is very contagious right?
Well I think I saw a fish that had TB in Petco. The fish was in one of the tanks where they keep plants for sell and their are a few fish in there too. The body was like your second pic; the spine curved and whacked out, odd masses and lesions, plus a hole or wound that look like a chunk of flesh was missing on the fish's head.
So if that fish did have TB, that whole tank is infected?
Posted 18 March 2010 - 09:26 PM
Posted 18 March 2010 - 09:33 PM
Posted 19 March 2010 - 01:58 PM
Fish TB is not very contagious and if caught early will have a very small impact on the rest of your aquarium members.
Luckily, fish TB is not very contagious, and as a result, if symptoms are noticed early, it will not have an effect on the other life in the aquarium.
I've read a lot of forum posts saying exactly the opposite, but IME that has not been the case.
Posted 19 March 2010 - 03:12 PM
Personally, I lost about a quarter of my fish to it, and that's out of over a hundred, so I wouldn't say the strain of mycobacteria in my tanks wasn't very contagious. I also was keeping up my maintenance, never letting my parameters get out of whack, quarantining new fish, etc.
Eden: I'm almost positive that the disease was transferred between my tropical and coldwater tanks by moving either plants, snails, or filters. I certainly didn't stick any tropical fish in with my goldies, so it could not have been direct fish to fish transmission.
Edited by paperdragon, 19 March 2010 - 03:14 PM.
Posted 30 March 2010 - 11:48 PM
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