The fact that factory farming creates large "lagoons" of hog waste always seemed like a pretty bad thing from a public health point of view. You wonder when some kind of awful disease is going to emerge from the big lakes of pig crap.
Until I read litbrit's post on this, I didn't realize that the current swine flu could be just that. She links to Tom Philpott's article in Grist, which describes how the outbreak originated in a part of Mexico where Smithfield has big hog farms and the waste apparently isn't being properly disposed of. This link is being picked up in the Mexican press (litbrit helpfully translates some stuff). In the American press, not so much.