Fungal infections can and do occur in horses. One variation of this results in the horse having white spots form on the body. This is a considerably rare event and most horses suffering from a fungal infection are often confused for simply being a uniquely coloured horse. Due to the coat result caused by external forces it is impossible for the horse to pass on the colour to the offspring.
Check out the Fungus Spots album to se pictures of horses with Fungus Spots:
Fungus Spots HorsesCheck out this album to see pictures of horses with fungus spots!