From: Ian A. York
Subject: Re: Retrovirus
Date: Sep 12 1996
Newsgroups: sci.med.immunology,sci.med

In article <5180ul$k4m@cnn.isc-br.com>,  <ACTURUS@planets.com> wrote:

>Thanks for the reply, are these retroviruses "new," or have they been around
>for awhile, and if they have been around for awhile, did they infect humans?
>Also, how are they generally treated in animals?

They are extremely ancient viruses; they've been around for millenia.  
They have infected humans for millenia as well.  It isn't clear how long 
HIV has been in the human population, but it's possible that it is a 
long-time human pathogen.  It's much clearer that the human 
T-lymphotrophic virus (HTLV), a rare cause of cancer particularly in 
Japan, has been floating around in humans for a long time.  There are 
also non-pathogenic retroviruses of humans (or at any rate 
retrovirus-like sequences with which no human disease has yet been 
associated) - the spumaviruses - which most likely have been parasites of 
humans since before humans were humans.  

Humans are a little unusual (though far from unique) among species in 
that, so far as I know, there aren't any oncogenic retroviruses (types C 
and D retroviruses) that infect them.  Since other primates have these 
viruses, it's either a fortunate happenstance, or the viruses have not 
yet been identified - which would mean they are rare; people have 
looked hard for them.

There's no treatment available for any retrovirus, whether human or 
animal.  The closest to being treatable is HIV, and you know how 
untreatable that is.  In some cases the tumours induced by the retrovirus 
can be treated - this is the same as for tumours in general.  

There are vaccines availabe for a handful of retroviruses.  Feline 
leukemia virus vaccine has been commercially available and widely used for 
over a decade now and works reasonably well - it isn't 100% effective, as 
with any vaccine.  

If you're interested in retroviruses, any introductory virology 
text will cover them in more detail, and more accurately, than you'll get 
from Usenet.

There's also a lot of useful information at the "Index Virum" page:
http://life.anu.edu.au/viruses/Ictv/fs_retro.htm
which gives taxonomic listings of known viruses, and you should also look 
through the mother of virology pages, 
http://www.bocklabs.wisc.edu/Welcome.html

Ian
-- 
      Ian York   (iayork@panix.com)  <http://www.panix.com/~iayork/>
      "-but as he was a York, I am rather inclined to suppose him a
       very respectable Man." -Jane Austen, The History of England