Seems alright so far. I'm not so sure about the tick part though. There's going to be issues with that. It'll cause a lot of death just because there aren't that many caves out there that they can find safety in. I don't know if its possible, but could we set up a "windchill" sort of thing, making the ticks only start if you've been in the region too long? That way, when they find a fire, they can go back out? That would let us control what areas are open to them, as all we need to do is create more fires or caves.
Oh. I've also got something of a guide up. I'll show it to you next time I get a chance.