(
I added the bold text for emphasis)
I was puzzled by the same question. Of course, since I'm not a microbiologist or, for that matter, a scientist (medical or otherwise), it did seem
to be a rather valid question: "Why would knowing
where AIDS/HIV first developed make any difference in developing a treatment?
I found a blog,
A.U.F.A.P. or
Artists United For Aids Prevention that focused on AIDS/HIV and this question was answered -- at
least to my satisfaction.

"The main challenge of developing a vaccine against HIV is its tremendous genetic diversity," he said.
Knowing the gamut of diversity within subtype B could be important for effectively developing and testing vaccines that will work in Haiti
SOURCE
Incidentally, the blog went on to provide a history of AIDS/HIV and it was extremely interesting.
HIV/AIDS Basic
Information
[edit on 11/2/2007 by benevolent tyrant]