[Jasonft]

Kudzu might still have some settlements in the far north and south cold regions with scavenger runs into the ruins, but other than high mountain areas and deep sea platforms there won't be that many big settlements. Hawaii and some islands *maybe*.

On the other hand I could see Australia being the last big 'clean' area on the planet. Flamethrower crews wearing bio-hazard suits regularly sweep the beaches to catch floating mats coming in from the ocean and maybe even an effort to sterilize the soil in nearby parts of Indonesia. It's not much. but it might be possible.

Edit: Depending of course on just how long ago the mutation happened.