Histoplasmosis Facts (Respiratory Disease)

The airborne histoplasmosis infection is passed to humans when they are exposed to the fungus Histoplasma capsulatum, most commonly found in bird and bat droppings (guano). The infection is most commonly found in workers who were exposed to airborne fungus spores without proper protection in cleaning and demolition projects. The fungus can also permeate soil contaminated by bird or bat droppings. An extremely serious and potentially fatal respiratory disease, proper protection during dropping cleanup is absolutely essential.

bird mess in building  worker cleaning bird mess  histoplasmosis in feces  histoplasmosis microscopic

Farmers, landscapers, roofers, and workers who clean droppings from building and property surfaces are most at risk. The fungus is especially common in large piles of feces, which can quickly accumulate with large quantities or birds or bats as well as pile up over time. The Histoplasma capsulatum fungus thrives in the damp droppings and soil, then once the droppings dry out, the fungus spores become airborne when contaminated material is disrupted. 

Warehouses, chicken and pigeon coops, poultry barns, barns, parks, HVAC plants, stations, and any other damp areas are especially at risk. Ghost towns, mines, and other areas can easily contain the dangerous spores, even if birds or bats have not been present in years. Histoplasmosis can only be caught through direct contact with the fungus spores; it is not passes from person to person. However, if multiple people are exposed to the same source (breathing in contaminated air), many may be sickened.


If a person develops symptoms of Histoplasmosis, they will do so within two weeks of exposure (normally 3-17 days). The most common symptoms include:

  • Fever
  • Chills
  • Dry Cough
  • Chest Discomfort
  • Headache
  • Muscle Aches
  • Joint Pain
  • Rash

Some people who have underlying lung problems or diseases experience tuberculosis-like symptoms, including a cough that brings up blood and weight loss.

In people with weakened immune systems, especially children and the elderly, more severe symptoms can occur. This stage is called Disseminated Histoplasmosis, which can affect eyes, liver, skin, adrenal glands, and the central nervous system. Medical treatment must be sought at this point, as this condition is usually fatal.

Wear Proper Protection

It is advisable to hire a professional in severe cases of pest bird or bat dropping cleanup. However, many companies choose to do the cleanup themselves, often by hiring workers who are unskilled in bird and bat dropping removal. The United States Centers for Disease Control and Prevention (CDC) explains the proper measures to reduce the risk of human exposure here: http://www.cdc.gov/niosh/docs/97-146/

Other Risks of Bird and Bat Droppings

In addition to Histoplasmosis, there are over 60 other transmissible diseases found in bird and bat droppings.

References Cited

"Diseases and Conditions: Histoplasmosis." Mayo Clinic. February 8, 2012. http://www.mayoclinic.org/diseases-conditions/histoplasmosis/basics/definition/con-20026585

"Histoplasmomsis - Protecting Workers at Risk." Centers for Disease Control and Prevention. December 2004. http://www.cdc.gov/niosh/docs/2005-109/default.html