This belief rests on two (contradictory) pillars: first, that parasites adapted to pigs would have a hard time adapting to humans, and, second, that because pigs and people have lived together for so long, any parasites likely to switch have already done so.

ECONOMIST: Pigged out

The consumers on free Gmail made excellent guinea pigs for tests, and their behavior told Google about how long people scanned items, say, or what they used in instant messaging.

FORBES: On The Cover/Top Stories

We have co-evolved with other species like cows and pigs, but our relationship with dogs and horses is special because they have served so long and so faithfully as friends and partners in many of our highest aspirations.

CNN: Should I still be grieving my horse's death?