C.neoformans is quite commonly present almost everywhere in the world, as well as the infection caused by it. It can be isolated from e.g. pigeon droppings, manure, fruit etc.To my knowledge it hasn't been proved yet that infection can be caused by dealing with pigeon droppings. Although I would consider the possibility of this species presence due to the flying by birds.
A large part of the micro-biota on the surface of plants are basidiomycetous yeasts and they include C neoformans and a number of very similar species. It is likely that C neoformans is present as part of the normal micro-biota of this habitat.