Bird and Bat Dropping Pathogens

Bird and bat droppings are reservoirs for opportunistic pathogens that can cause important human diseases: histoplasmosis, cryptococcosis and psittacosis. Histoplasmosis is caused by the fungus Histoplasma capsulatum. Histoplasma lives in the environment, particularly in soil that contains large quantities of bird or bat droppings. Humans can develop histoplasmosis by breathing in microscopic fungal spores.

Cryptococcosis is an infection caused by fungi that belong to the genus Cryptococcus. While there are over 30 different species of Cryptococcus, one species of primary concern is Cryptococcus neoformans. Cryptococcus neoformans is found in soil throughout the world, usually in association with the presence of bird droppings, especially pigeon droppings. It is commonly found within debris from pigeon roosts and soil contaminated with decaying pigeon or chicken droppings. Infection usually occurs through inhalation of spores from the environment.

Another pathogen found in bird droppings is the bacteria Chlamydia psittaci. Chlamydia psittaci can cause psittacosis in humans due to the transmission of the bacteria from infected birds. Infected birds shed the bacteria in their droppings and respiratory secretions. As these droppings and secretions dry, dust particles containing the infectious Chlamydia psittaci bacteria can become aerosolized. The most common way someone becomes infected is by breathing in the dust from these dried secretions.