Public health officials in Tennessee are responding to a regional outbreak of histoplasmosis, a potentially serious lung infection caused by a soil-dwelling fungus. More than 35 confirmed cases have been reported within a three-month period in Maury County and Williamson County, prompting heightened surveillance and public health warnings.

The outbreak has raised concerns due to the number of people affected in a relatively short time frame, as well as reports of severe illness among some patients. While investigations are ongoing, state epidemiologists emphasize that histoplasmosis is not contagious between people and that the overall risk to the general population remains low.

What Is Histoplasmosis

Histoplasmosis is an infection caused by inhaling spores of the fungus Histoplasma capsulatum, which is commonly found in soil contaminated with bird or bat droppings. The fungus becomes airborne when soil is disturbed, allowing spores to be inhaled into the lungs.

The infection is endemic in parts of the United States, particularly in river valleys and areas with large bird or bat populations. Most people exposed to the fungus do not become ill, but in some cases, the infection can cause significant respiratory disease.

Details of the Tennessee Outbreak

According to data presented by the Tennessee Department of Health, over 35 cases of histoplasmosis were confirmed in the Maury and Williamson County area over a three-month period. State officials reported that the average age of infected individuals is approximately 50 years.

A local family has publicly stated that a woman died after contracting histoplasmosis, with laboratory confirmation returned shortly after her death. However, state epidemiologists have cautioned that investigations are still underway and that histoplasmosis has not yet been confirmed as the direct cause of any fatalities linked to the outbreak.

Officials also noted that no single exposure source has been identified, suggesting that multiple environmental exposures may be involved.

How Exposure Occurs

Exposure to Histoplasma capsulatum occurs when people breathe in fungal spores released into the air after soil disruption. Activities that increase risk include construction, excavation, farming, landscaping, cleaning areas with bird or bat droppings, or spending prolonged time in dusty outdoor environments.

Because the spores are microscopic, exposure often goes unnoticed. People are typically unaware they have inhaled them, making prevention difficult without targeted awareness.

Importantly, histoplasmosis does not spread from person to person and cannot be transmitted from humans to animals.

Symptoms and Clinical Presentation

Symptoms of histoplasmosis usually appear between three and 17 days after exposure. The illness often resembles common respiratory infections, which contributes to delayed diagnosis.

Reported symptoms include:

fever
cough
chest pain
fatigue or extreme tiredness
headache
body aches
chills

In mild cases, symptoms may resolve without treatment. However, severe disease can develop, particularly when the infection spreads beyond the lungs.

Why the Disease Is Often Missed

One of the challenges highlighted by the Tennessee outbreak is that histoplasmosis is frequently misdiagnosed. Because symptoms resemble influenza, COVID-19, or bacterial pneumonia, patients may initially receive antibiotics, which are ineffective against fungal infections.

Delayed recognition can allow the disease to progress, especially in high-risk individuals. Health experts emphasize that fungal infections are often overlooked in routine clinical practice.

Who Is Most at Risk

While most healthy individuals exposed to Histoplasma capsulatum do not become ill, certain groups face a higher risk of severe disease.

These include:

people with weakened immune systems
individuals undergoing chemotherapy
organ transplant recipients
older adults
people with prolonged or intense exposure to fungal spores

Diagnosis and Treatment Options

Histoplasmosis can be diagnosed through laboratory testing of blood or urine samples. Additional diagnostic tools may include chest X-rays, CT scans, respiratory fluid analysis, or tissue biopsy in complex cases.

Most people with mild infections do not require treatment. However, moderate to severe cases are treated with antifungal medications, which can be highly effective when administered early.

Conclusion

The histoplasmosis outbreak in Tennessee serves as a reminder that environmental fungal pathogens can pose serious health risks, particularly when exposure coincides with vulnerable populations. While most infections remain mild, the potential for severe disease underscores the importance of early diagnosis, clinician awareness, and public health surveillance.

As investigations continue, health officials emphasize that informed precautions and timely medical evaluation can significantly reduce the impact of histoplasmosis and similar fungal infections.