What Employers Need to Know about Histoplasmosis

What is histoplasmosis?

Histoplasmosis is an infection caused by a fungus called Histoplasma capsulatum. The 

fungus lives in the environment, particularly soil that contains large amounts of bird or bat 

droppings. People can get histoplasmosis after breathing in the microscopic fungal spores 

(also known as conidia) from the air. In the United States, Histoplasma mainly lives in the 

central and eastern states, particularly areas around the Ohio and Mississippi River Valleys. Areas with Histoplasmosis

This map of the United States shows CDC’s current estimate of where the fungi that cause 

histoplasmosis lives in the environment. Darker shading shows areas where Histoplasma is more 

likely to live and diagonal shading shows the potential range of Histoplasma. These fungi are not 

distributed evenly in the shaded areas, might not be present everywhere in the shaded areas, and 

can also be outside of the shaded areas.

What are the symptoms of histoplasmosis?

Most people who breathe in the spores don’t get sick, but those who do may have a fever, 

cough, and fatigue. Symptoms usually appear between 3 and 17 days after a person 

breathes in the fungal spores. In some people, the infection can become severe and 

spread from the lungs to other parts of the body. This is more common in people with 

weakened immune systems or other medical conditions.

Some activities have risks for exposure to Histoplasma

Disturbance of large accumulations of bird or bat droppings (scraping 

droppings from a bridge, shoveling droppings from a building, cleaning a 

chicken coop)

 Soil disruption (digging or excavation)

 Plant matter disruption (handling trees, landscaping)

 Demolition, construction, or renovation

 Working in caves
In areas where Histoplasma is common, some people may have a higher chance of 

getting histoplasmosis. Examples include people who work in:

• Construction and demolition

• Mining, quarrying, and oil and gas extraction

• Agriculture and forestry

• Any jobs that involve activities listed on page 1

How to prevent histoplasmosis in the workplace

The best way to prevent exposure to Histoplasma is to prevent the accumulation of bird or

bat droppings in the first place. This can be accomplished by excluding bats and birds from 

buildings. If accumulation of bat or bird droppings must be removed, or if construction, 

excavation, or demolition must be done in areas where Histoplasma is common, employers 

should:

• Develop a site safety plan to minimize workplace exposures.

• Reduce or eliminate dust. Spray water or use other dust suppression techniques.

• Dispose of any material that might be contaminated with Histoplasma safely while following 

state and local requirements.

• Post health risk warnings in areas known or suspected to be contaminated with Histoplasma. 

• Train workers so they understand the potential risks and how to protect themselves.

• Provide personal protective equipment (PPE) and associated training to workers.

• Encourage workers with workplace exposures to Histoplasma or symptoms of histoplasmosis 

to seek a medical evaluation with a healthcare provider.

Personal Protective Equipment 

can be used to protect workers 

from exposures to Histoplasma. 

Disposable protective clothing 

and shoe coverings can help 

prevent spreading spores to 

other places like a worker’s car or 

home.

For more information on histoplasmosis and how to protect your employees, please visit: 

CDC’s histoplasmosis website: https://www.cdc.gov/fungal/diseases/histoplasmosis/

CDC/NIOSH’s histoplasmosis website https://www.cdc.gov/niosh/topics/histoplasmosis/

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DHHS (NIOSH) Publication No. 2022-103

DOI Number: https://doi.org/10.26616/NIOSHPUB2022103

December 2021

Coveralls with Hood

NIOSH-approved 

Respirator

Eye Protection

Gloves

Disposable Shoe

Coverings