Well as stated in my first post, the zombies will have the same likeliness as in The Walking Dead. It will be an infection that everyone is believed to have and you only turn if you are bitten, scratched, or die. A cure is not yet established.  

As for the geography, Walking Dead Wiki infers that everyone on the planet has the infection. However, as all forms of news (radio, tv, wifi, etc.) would be inaccessable to our characters, they would not know if other countries are infected or not.