LOST Revisited: Season 6, Episode 3 – “What Kate Did”

The question is, what is infecting and claiming people? It wouldn’t seem to be Jacob, and Smokey’s hands are kind of full right now, what with having human form and all. Why does the spring heal some and infect others? I’d really like to know what people think, because this is incredibly intriguing. And how does Dogen have all his information? It seems like they don’t have direct contact with Jacob, but they know a lot of stuff about a lot of people.