Re: [RML] Tropical Fish Granuloma

Bruce Hansen (bhansen at
Tue, 16 Jun 1998 21:07:44 +1000

My understanding is that each species of Mycobacterium is more or less
specific to a particular group of animals so for example Piscine TB will
tend to occur for the most part in cold-blooded animals such as fish ,
reptiles, amphibians etc

Those few cases that occur in humans tend to be confined to limbs where
body temperatures are lower. However we have to be careful in translating
this to the fish situation as some species of fish will be stressed at
temps outside their normal range ( both above and below) so their immunity
and immune responses may be adversely impaired while the invading organism
may have it's success enhanced

To some extent the old equation of Host immunity Vs organism virulence
still is the simplest way to start looking at it.

The factors that modify these 2 basics then start to become important in
explaining the inconsistencies in the observations and conclusions.


Bruce Hansen, ANGFA, caring for our aquatic ecosystems.

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> From: Adrian R. Tappin <atappin at>
> To: rainbowfish at
> Subject: Re: [RML] Tropical Fish Granuloma
> Date: Tuesday, 16 June 1998 15:09
> An example that comes to mind is temperature - High temperatures in my
> opinion is one such contributing factor. Now whether this is because the
> bacteria becomes more virulent in warmer temperatures or that the
> rainbowfish are under stress at higher temperatures, I don't really know
> perhaps its both? It may be that we can providing perfect water
> diet etc., yet once the temperature goes above a certain level the fish
> at risk. Also how do we acquire the bacteria in the first place and can
> avoid getting it?