Pigeons are perfect disease carriers and can travel great distances. Birds and their droppings can carry over 60 diseases. Also harboring different parasites, such as ticks and mites as well. A respiratory infection called histoplasmosis can develop from breathing a fungus that grows on the droppings. Candidiasis and Cryptococcosis are yeast infections spread by pigeons from their intestinal track through droppings. These diseases are transmitted to humans by breathing the fungus spores in the droppings, this is especially true if the droppings are dry and then get stirred-up into the air.