From: dfield@zeus.calpoly.edu (InfoSpunj (Dan Field))
Newsgroups: sci.med
Subject: Re: What homing device does a virus use?
Date: 20 Nov 92 03:01:56 GMT
Organization: California Polytechnic State University, San Luis Obispo

In article <lgilbnINN61a@news.bbn.com> levin@bbn.com (Joel B Levin) writes:
>In <lgihacINN6hm@peaches.cs.utexas.edu> Russell Turpin says:
>|In article <17491@pitt.UUCP> geb@cs.pitt.edu (Gordon Banks) writes:
>|> The same way that plant seeds distinguish soil from rocks: they don't, ...
>|
>|For once, you lose me.  Seeds clearly do distinguish soil from
>|rocks: they grow in the former and die on the latter.  
>
>I liked the way Gordon phrased it; I suspect he answered a question
>different from what you meant to ask.  He says (if I may presume to
>interpret) that the organisms don't "home in" on the particular areas
>they infect; rather that, like seeds scattered in the wind, they show
>up everywhere but only find conditions suitable for growth (soil) in
>these particular areas and fail to thrive everywhere else.
>
>|		       Now ... What are the mechanisms in the case
>|of the question I posed?
>
>Now -- if you are asking why the viruses grow in certain areas and not
>in others, that is a different question.  I assume it has to do with
>availability of warmth, moisture, absence of direct exposure to air,
>etc.; one of the doctors or scientists will have to answer that
>question, which I don't think was exactly what you asked. 

Doesn't the herpes virus remain in the nerve at the end of which it was
first innoculated?  I've heard that it CAN infect other body parts, like
hands, if it has an opportunity to contact a skin break there.  

Contact from an infected body part to certain other body parts is 
more likely than to certain others (such as genital-genital, lip-lip
contact, and various combinations thereof).  Once infection occurs
at one site, however, I don't think it can infect other parts on
the same person; for example, a person orally infected with one of the
types of the herpes virus won't have genital lesions unless a separate
infection has occurred there.  Am I correct?  I've also heard reference
to "self transmission," or transmission to other body parts by the
same patient.

So here's my rephrasing of what I got out of the original question:
what mechanism (or lack thereof) prevents the herpes virus from
launching a systemic attack, or of any apparent navigation at all
inside the body of it's host?

My personal speculation (uninformed) is that it would be related to the
difficulty in developing an effective herpes vaccine; even if you have
antibodies to the herpes virus, they're not going to do much in the
bloodstream if the virus is not appreciably circulating in the blood 
anyway, but rather in your nervous system.  The antibidies would,
I would imagine, be able to interfere with the ability of the virus
to infect other parts of the body by attacking it in the bloodstream and
lymph.

Is this correct?   Also, any info on vaccine development for herpes
would be interesting.  Please add it to this discussion if you have
it! 

-- 

                                -Daniel R. Field
                                 dfield@nike.calpoly.edu