First of all, thanks to all who have replied, did a bit of research and added to this thread. By the way, it doesn't necessarily have to be a Corrido; any type of Spanish-language song will do. About the 1918 Influenza, aka Spanish Flu, from what I've read and seen (if you get a chance, check out the PBS doc: American Experience: Influenza 1918), the   Influenza appears to have begun in Kansas on an army post - soldiers were burning manure. The spread of the flu then followed the railroads - soldiers moving about the country and eventually being sent to Europe to fight in WWI. One of the reasons offered as to why it's called the Spanish flu is that a disproportionate number of people died in Spain, leading people to believe that it originated here, although it's also been suggested that officials at the time sought to pin blame abroad.