What Workers Should 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 very small 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.

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 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

Areas with 

Histoplasmosis
In areas where Histoplasma is common, you may have a higher chance of getting 

histoplasmosis if you work in:

• Construction and demolition

• Mining, quarrying, and oil and gas extraction

• Agriculture and forestry

• Any jobs that involve activities listed on page 1

Protect yourself from histoplasmosis

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 you must remove accumulations of bat or bird droppings or if you are doing 

construction, excavation, or demolition in areas where Histoplasma is common, try to eliminate 

or reduce dust. For example, spray water or use other dust suppression techniques.

Coveralls with Hood

NIOSH-approved 

Respirator

Eye Protection

Gloves

Disposable Shoe

Coverings

Personal protective equipment 

(PPE) may also help protect you 

from Histoplasma. Disposable 

protective clothing and shoe 

coverings can help prevent 

spreading spores to other 

places like your car or home. 

Talk to your crew leader or 

supervisor about selecting the 

appropriate PPE.

If you think that you have been exposed to Histoplasma at work or have symptoms 

of histoplasmosis:

• Contact your crew leader or supervisor and your Occupational Health or Risk Management 

Department

• Contact your local city, country, or state health department if your workplace does not have 

the above services

• Seek a medical evaluation by a healthcare provider

• Talk to your healthcare provider about testing for histoplasmosis

For more information on histoplasmosis and how to protect yourself, 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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1-800-CDC-INFO (1-800-232-4636) | TTY: 1-888-232-6348

CDC/NIOSH INFO: cdc.gov/info | cdc.gov/niosh

Monthly NIOSH eNews: cdc.gov/niosh/eNews

DHHS (NIOSH) Publication No. 2022-104

DOI Number: https://doi.org/10.26616/NIOSHPUB2022104

December 2021