Quote from Mecha-HewittGreenland is easy but I do agree it's a hit or miss sometimes, but nothing like Madagascar. China has the most land area so it's always the best place to start. Max the spreadability first before introducing symptoms because the country only starts curing itself when a certain cash limit has been reached in the budgetting for a cure. So if you can get at least 1 germ in 1 country like greenland you're good once you set the non-lethal symptoms in.
Oh man, a friend of mine does that all the time in his games. In fact, one time he said he managed to infect nearly everyone on the planet before triggering symptoms so that there was a really fast, mass extinction in a sense.