From: "Paul M. Karagianis" <KARYPM%SJUVM.BITNET@VM.USC.EDU>
Subject:      Re: The Myth of Heterosexual AIDS
Note: Copyright 1992, Dan R. Greening. Non-commercial reproduction allowed.
Archive-Number: 5963
Organization: unspecified
Date:         Sat, 22 Aug 92 19:55:02 EDT

This was part of a previous excerpt I entered, but I'm repeating it
to provide background in a different context.

The Thursday edition of the following source:

> From: matthew@ooc.uva.nl (Matthew Lewis)
> Subject: Conference Newspaper -Tuesday, 21 July - part 1
> Date: 21 Jul 92 20:06:46 GMT
> Organization: Center for Innovation and Cooperative Technology,
>               University of Amsterdam

  ...contains the following excerpt...

> Two Thai subtypes identified
>
> Further insights into the mysterious ways of HIV subtypes have
> come from Dr Chin-Yih Ou and Dr Bruce Weniger of the Centers for
> Disease Control HIV/AIDS collaboration project in Bangkok.  Ou
> reported that two viral subtypes have been found in Thailand. One
> type is in patients likely to have contracted HIV via sexual
> transmission, while the other is confined largely to intravenous
> drug users.  None of the Thai patients had contracted HIV through
> blood transfusion.  As in related data presented previously by Dr
> Gerald Myers, no one has been found to be infected with both
> subtypes.
> The subtype found in female prostitutes, their male clients and the
> pregnant wives of those clients closely resembles the HIV subtype
> most prominent in Africa, including strains Uganda 455, Zaire Z6,
> NDK and MAL.
> The subtype found in drug users is essentially the same as that
> found in the North American and European strains LAI and ADA.
> The Thai data show a 22% genetic divergence between the two
> subtypes, indicating that HIV-1 was introduced twice into Thailand
> and that the current subtypes did not evolve from a common
> precursor virus after initial introduction into the country, Ou said.
> He added: "We do not fully understand the reasons for this
> segregation.  It could be that there is little high-risk contact
> between intravenous drug users and prostitutes and that the HIV
> epidemics are quite separate between these groups."  Other
> theories are that there may be biological differences in how easily
> the two subtypes can be transmitted, or that infection with one
> viral subtype may block infection with another.
>
> The Thai programme researchers are currently trying to determine
> whether the subtypes differ in pathogenicity.  They are running
> cohort studies, in prostitutes, young men and pregnant women, and
> they are now going back to determine the viral subtypes in each of
> these patients. This work should reveal some useful information
> about the relation of HIV subtypes to the progression of the disease.

    The usual explanations for the difference in the apparent efficiancy
of heterosexual transmission between the U.S./Europe, where the disease
appears to be non-self-sustaining via heterosexual vector only, and
Africa/Asia where it obviously is, boil down to a difference in social
values.  "Those people" have more sex with more partners under less
hygenic conditions; they are more likely to have secondary STD's, anal
sex, bi-sexual experiences and use prostitutes.  That's a reasonable
explanation (despite the undercurrent of racism I sometimes think I
hear in these arguments) and I will concede that it's probably correct.

But what if it isn't?  What if things are simply just what they look
like?  We, in the U.S./Europe, have a subtype that isn't particularly
contagious.  "They" are dealing with a subtype that is.  Historically
the most successful subtype will be the one that spreads most easily,
so as far as the non-IDU heterosexual general population of the U.S.
is concerned the "real" pandemic just hasn't gotten here yet.
                                     -Kary.

btw: Our system spell-checker went MIA so please accept my apologies
     in advance.  ;)
Newsgroups: sci.med.aids