I saw a film a while ago about colonial america and I was wondering what it's called?

erm.. well a few years ago now I watched a film on TV about the colonialists in america travelling with bullock carts. erm if it helps I remember there were fights between the native people and the colonialists and a woman got her leg run over by a cart and had it amputated but died in the process. also there was a huge thing about cholorea and they had to split up into people who had been in contact with the woman who died of cholorea and the people who hadn't. its really annoying because its such a good film and i want to see it agian. grrrr