Humans can get histoplasmosis from bird droppings, which affects the lungs. I don't know if it can affect ferrets, but given that it affects lungs, I wouldn't want to take the chance. (cut and pasted) Several thousand cases of food poisoning (Salmonella) occur every year. Food poisoning is caused by the Salmonella bacterium getting into left out food. A main source of the Salmonella bacteria is dried fecal dust from air vents covered in bird droppings. [can also come from fecal dust, etc. brought in on shoes] Diseases Associated with Pest Birds Bacterial - Paratyphoid, Vibriosis, Salmonella, Listeriosis & Pasteurellosis Viral - Encephalitis, Meningitis, Newcastle Disease & St. Louis Encephalitis Fungal - Histoplasmosis, Candidiasis, Sarcosporidiosias & Blastomycosis Protozoal - Toxoplasmosis, Trichomoniasis & American Trypansomiasis [Posted in FML issue 4807]