Well one person gets a diesease or sickness and then they pass it to someone else then that person passes it to someone else and it goes like this till pretty much the alot of people have it.
the flu came from where we belive to be Mexico ,but lets not jump to canclutions it might had come from the U.S and imported to Mexico or imported to the U.S by some other country!!!!!
Well i really don't know but in my moms work people have been saying that this one lady who came from Canada to Mexico that in the plane that she was in she had infected people with her desease .but...