Alrighty...
I like the idea, but it really needs more depth. Once the strategy is figured out, that's it. There needs to be more than one way to win.
For those who still haven't got it, the key to winning is infectivity. Remember it says you get points each turn for the number of people INFECTED. If people are dying or you can tell they're sick, the authorities of medicine are going to know its spreading. Get your lethalty and visibility down to 0 and boost your infectivity, taking turns until every single person in the world is infected. Then, when you have all your points, check off every possible ailement and hit the human race like a steamroller. You will go from 500 to 180,000 deaths in a single turn, and get the most points. :)
If public transit is shut down before each country has infected people, quit the game and try again. Continuing from that point is futile.
As it is, people have tampered with the game and the scoreboard has suffered as a result. Trying for a high score seems pointless.
I still like the game. 7/10, 5 in the Portal.