From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med
Subject: Re: Herpes--Origin and identification
Date: 30 Apr 1998 01:57:35 GMT

In <3548ae8e.9835639@news.pipeline.com> p_riley@pipeline.com (Patrick
Riley) writes:

>I understand that Genital Herpes and Cold-sore-around-the-mouth-type
>Herpes are not supposed to be the same disease but since they're both
>called Herpes there must be or have been at some time a connection.
>
>Is one a mutation of the other?

    Almost surely.  The genes are 50% identical.  Herpes I likes the
mouth and Herpes II the genitals, but either will infect either place.



>Why doesn't the body's immune system kill them off?


   They hide in the nerves where the immune cells can't see them.  Also
the herpese viral genes aren't transcribed most of the time, except for
one gene just "ticking over" and making a little bit of repressor
protein, which is undoubtedly a sort of time bomb, waiting for
conditions in which the entire virus should be transcribed again, to
de-repress the rest of the genes.  The virus is then transcribed and
the pieces move down the nerve to the end, where it breaks out and
infects tissues.  Cells have interferon inside them, which destroys
viral RNA, but it apparently doesn't do too well against the herpes
when it's in the suspended animation state, not making much viral mRNA.

                                   Steve Harris, M.D.