Scientists from the US Centers for Disease Control and Prevention (CDC) have discovered evidence of a new influenza type A virus in Guatemalan fruit bats.
"...for reassortment to occur, the bat flu virus would have to be capable of infecting a different animal, such as a pig, horse or dog, at the same time as a human flu virus.
So far, the bat flu virus has only been found in little yellow-shouldered bats. These fruit bats are not native to the US, but quite common in Central and South America. The bats don't bite people, but it is feasible they could shed the virus onto foods like fruit and vegetables that are then eaten by humans and other animals."
And if you watched "Contagion", you will remember the bulldozer knocking down the tree, which disturbed the bat, which roosted in a pigpen, where pigs ate the faeces, and - recombination occurred!