Bat guano is a health hazard and great care must be taken when removing it from old homes or barns. This is because bat droppings often contain the fungus Histoplasma capsulatum. The fungus can be found in most temperate climates around the world, but is most commonly found in river valleys in Central and South America and in the United States around the Mississippi River. These regions have acidic, damp soil that the fungus prefers and once contaminated the soil can remain a hazard for years. Bats are often infected with the fungus and once they are infected their droppings contain a high concentration of fungus.
If a person inhales the spores from Histoplasma capsulatum they can contract a respiratory disease called histoplasmosis. Most people do not have any symptoms and the infection can be short-lived and mild. Some symptoms include fatigue, fever, chills, chest pains and cough. However, the young, elderly, and immune-compromised can have a long-term chronic infection that can last months to years and can be fatal. The disease is treated with anti-fungal medicines.
If you are removing bat guano health agencies recommend that you wear protective clothing, gloves, and a respirator or mask. They also recommend spraying dried droppings with water before cleaning to prevent the fungus spores from becoming airborne.
Several countries, including Cuba, Jamaica, and Mexico, sell bat guano for use as a fertilizer. The guano is typically “harvested” from bat caves. It is rarely sterilized and both the workers that harvest the guano and the gardeners that use it are at risk for histoplasmosis. Additionally, environmentalists worry that continual harvesting the guano disturbs the bats, kills other organisms in the caves, and destroys cave formations.