Fascinating article. Also, in the same issue, one by Danny Douek on
HIV pathogenesis.

George M. Carter

**
http://www.prn.org/prn_nb_cntnt/vol10/num3/hahn_frm.htm
Tracing the Origin of the AIDS Pandemic
Beatrice H. Hahn, MD
Professor of Medicine and Microbiology
University of Alabama at Birmingham
Birmingham, Alabama

Summary by Tim Horn
Edited by Lucia Torian, PhD

For those lucky enough to be in attendance, the keynote lecture
delivered at the 6th Conference on Retroviruses and Opportunistic
Infections (CROI) at the end of January 1999 was nothing short of a
jaw-dropping experience. Dr. Beatrice Hahn of the University of
Alabama at Birmingham presented the first concrete evidence of the
primate origin of HIV-1, the much more prevalent of the HIV types
responsible for the AIDS pandemic. The official report of her team’s
findings, published in a February 1999 issue of Science, was a no less
captivating example of seminal scientific research (Gao, 1999).

Since 1999, Dr. Hahn’s group has been working tirelessly in the
laboratory and in the chimpanzee communities of sub-Saharan Africa to
illuminate the pathways leading to the emergence of HIV-1, the
adaptive changes that followed, and the mechanisms underlying its
pathogenicity in humans. The genetic similarities between chimpanzees
and humans—they share more than 98% sequence identity across their
genomes (Watanabe, 2004)—and the newly demonstrated relationship
between HIV and SIV may be useful to researchers searching for key
differences in virus-host interactions that may explain why and how
HIV causes immune deficiency in humans, while SIV is nonpathogenic to
its natural host. It is this research that continues to guide current
studies evaluating the susceptibility of humans to zoonoses such as
AIDS and may guide the development of new treatments and vaccines.
The Origin of HIV and SIV

There are two known genetically distinct AIDS viruses: human
immunodeficiency virus-1 (HIV-1) and human immunodeficiency virus-2
(HIV-2). HIV-1 is divided into three major clades, groups M, N and O;
group M is the clade most widely distributed and associated with the
majority of disease globally. Both HIV-1 and HIV-2 are of primate
origin. The origin of HIV-2 has been established to be the sooty
mangabey (Cercocebus atys), an Old World monkey of Guinea Bissau,
Gabon, and Cameroon (Hirsch, 1989; Gao, 1992). The origin of HIV-1 is
the central common subspecies of chimpanzee (see Figure 1).

see site for rest of article.