Growth of Cryptococcus neoformans in UV-irradiated excreta of pigeons.

UV irradiation of pigeon droppings resulted in an increased concentration of some inhibitors (peroxides) of growth of Cryptococcus neofarmans. This may be, in addition to the direct germicidal action of sunshine, another cause of the rare occurrence of this fungus in pigeon droppings on unsheltered sites in natural habitats.