Watched this a couple of weeks ago and it's very, very interesting. New discoveries and some great explanations as to why this epidemic is such a huge problem, and why it's imperative they find a cure.
Part 2: http://www.youtube.com/watch?v=cSmkKbrDOYo&feature=related
Part 3: http://www.youtube.com/watch?v=tKYGOjVbAvk&feature=relmfu
Part 4: http://www.youtube.com/watch?v=J7D0Ai63sr8&feature=relmfu
Part 5: http://www.youtube.com/watch?v=TMzCOwfAV0g&feature=relmfu