Well I think it goes without saying that it's a good idea not to step in vomit or poop, dog poo is dangerous. It's not a problem if you do just wash your shoes and clean them thoroughly. I cleaned poo twice off an old pair of trainers, 3rd time was the kick up the bum to just throw them in the bin and pay more attention to where I step It is literally everywhere here even right outside my front door so it's not easy.