Initially called an "outbreak", widespread H1N1 infection was first recognized in the state of Veracruz, Mexico, with evidence that the virus had been present for months before it was officially called an "epidemic"
I don't think we're actually sure where swine flu originated. It was first identified in America, but that might just be because their flu surveillance is better than other countries.
Initially called an "outbreak", widespread H1N1 infection was first recognized in the state of Veracruz, Mexico, with evidence that the virus had been present for months before it was officially called an "epidemic"
https://en.wikipedia.org/wiki/2009_flu_pandemic#History