Survive the apocalypse

The whole world has been ravaged by a virus that has turned people into flesh eating monsters. There are small pockets of survivors but the majority of the worlds population is dead, or worse. Supplies are hard to find and ammunition even harder to find. There's one large settlement left with a couple hundred people. But every other settlement is small 10-20 people max. The disease luckily only affects humans. It is transferred by bite or scratch.