Acute Histoplasmosis Outbreak Investigation — Williamson and Maury Counties, Tennessee, 2025
- Presentation Day/Time: Friday, April 24, 1:05 PM
- Presenter: Emma Taylor-Salmon, MD, Tennessee Department of Health
The Issue
- Histoplasmosis is an invasive fungal infection caused by inhaling spores found in soil. Most people with histoplasmosis don't get sick or experience only mild flu-like symptoms and improve without treatment. However, in November 2025, the Tennessee Department of Health (TDH) was notified of an outbreak of acute histoplasmosis along the border of neighboring Williamson and Maury Counties.
What We Did
- We identified additional patients and investigated potential exposures.
What We Found
- We identified 40 cases in the autumn of 2025 in people who resided or spent significant time within a 3.8-mile radius. Twenty-six patients were hospitalized and three died. The majority (65%) of patients were immunosuppressed, and these patients were 13.8-times more likely to be hospitalized. In spite of an extensive and in-depth investigation, no exposure was identified.
What This Means
- This outbreak highlights the knowledge gaps in histoplasmosis epidemiology, and the need to increase awareness of the disease.
