And the rest of the world?

[Luna Guardian]

We know what happened somewhat. It is covered in season 3 with "Beyond Our Walls". But after Ft. Irwin and Boulder became the last large safe havens in the US we know nothing. There were outbreaks in other countries (I don't remember which ones though) and given that Irwin lost contact with other countries we can infer that the world has gone to shit. (knowing full well that Kc wouldn't just excuse the fact that there were US naval ships stationed all across the world)

Well, we can also surmise that Russia at least is more or less intact, due to the lack of a Dead Hand or Perimeter response. Also, if all the US ships at sea were lost with all hands, doesn't that seem a little odd? Yes, it is entirely possible that one or two carrier groups would have some ships infested, but all of them with all the ships? I think this is simply a sacrifice that had to be made in detail due to scope restrictions and the fact that it did not matter to the story as it was told.

Ink is a special zombie because of his elite intelligence as a human. The fact that he had an irrational fear of dying and stumbled on the petroglyphs allowed him to control other zombies. The fact that he was paranoid solidified his overriding motivation as a zombie to defeat the survivor groups around him. And the fact that he was a highly skilled, highly trained chemist gave him the tools to develop the Behemoths and the Little Ones.

There probably are no Little Ones/Behemoths to worry about elsewhere in the world, but that doesn't mean there are no more smart ones out there. And maybe some smart ones were super-skilled at medicine and have developed zombies that are resistant to being killed or maybe there are smart ones more mechanically inclined who have developed robotically enhanced zombies. Who knows?

It is more than likely, almost certain in fact, that there are smart zombies all over the world IF the outbreaks were large scale enough. Without anything to back my claim, I would say that you need to be of Mensa level IQ in order to become a smart one, and Ink had a rather unique set of characteristics that made him the threat he was and allowed him to organize and control the zedheads. The chances of there being others like him are very slim, so given how the zombie gas was in the States and the other parts of the world only being infected by individual turners, it is conveivable, in my humble opinion, that at least remote areas with natural defences (such as distance, mountains, large rivers, open sea...) are still in good condition, though fully aware of the new dangerous world they may live in.

That being said, the UK is screwed. Police not having firearms, civilians largely unarmed and a huge population density probably made it a zombie buffet. At least England.