Tue Sep 26 13:43:38 EST 1995
In article <Pine.A32.3.91j.950921155002.118037D-100000 at homer12.u.washington.edu>, Jeffrey Jackson <jeffj at u.washington.edu> says:
>I'm a second year grad student in Immunology who's also an avid
>recreational salmon fisherman. I have a question that combines those
>two interests. That is: why do Pacific salmon, when they reenter fresh
>water become infected with all the various nasties that their particular
>home streams have to offer. I've come up with two explanations, but I
>have problems with both (besides the fact that they're way too simplistic).
>Does immune shutdown occur in the adults?
>Is death the necessary result of the physiological changes that occur
>upon reentry into fresh water and opportunistic infection just a
>Do the physiological changes that occur happen in landlocked salmon as
>Enough for now, thanks for reading this far.
Jeff, Basically the story seems to go as follows:
as the reproductive season approaches and the salmon come in, their
reproductive steroids begin to increase as well as the cortisol titers.
This seems to cause large scale immunosuppression and even direct
leucocyte cell death (due to cytoloic testosterone receptors). A lot
of the work currently being done in fish immunology is attempting to
understand some of the tremendous fish kills that are seen, -particularly
in the salmonids (both anadromous and landlocked species). While the full
causes for these effects are still unknown, it does seem that
steroid-induced immunosuppression is taking its toll.
That's all that I know, if anyone else has any information I would
appreciate hearing about it. My research is on this very subject -
just not salmonids.
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