QUOTE : If it weren't for the economy operated by humans constantly assailing the wild, encroaching upon it, tearing into it, chopping it up, destroying it with a zeal bordering on lust for extermination, these things wouldn't happen. The pathogens would not come leaping towards us. They would be secure among their natural hosts. But when those hosts are cornered, stressed, expelled and killed, they have two options: go extinct or jump.