[Frost__2001]

28 days later had nothing to do with Zombies, it was a viral outbreak to humans, not killing them but infecting them, and thus the human killing.

But yeah I don't think something like can be kept contained if infact it's in mosquitoes in that region, it's only a mater of time before it moves into other regions by other mosquitoes or by it's victoms infecting other mosquitoes when they leave the region. A good example of this would be the current one moving across Canada that was never here 10 years ago.