Do items left on the ground in the wilderness stay there overnight

When you're infected, you have a 50% chance of dying overnight, every night. You will not, however, infect fellow citizens. The infection stays local to you and you're not going to accidentally decimate your town. The worst that can happen is you die overnight and they either have to water your body down or drag it out into the wasteland.

Do not sacrifice yourself out of fear of this; I've managed to survive two nights in a row in spite of being infected and I can confirm you're more valuable to your town if you manage to stay alive.

There's a drug called the Paracetoid 7g which will cure your infection; in order to get it you're going to have to mix pharmaceutical products together and hope you're lucky.

As a side note, if you get infected via wound, it's not enough just to take the drug; you need to bandage the wound or the infection will return the next day.

As of Season 2 — we can now camp outside.