A good place to start is the Encyclopedia Britannica article on Botswana:



http://www.britannica.com/eb/article-43897/Botswana

It seems like life expectancy has really declined because of AIDS. According to the article below, it seems like nearly 40% of the adults are HIV+ and that life expectancy is below 40 years! Yikes!

Reference: Botswana battles against 'extinction'