Soil fungus are the leading cause of fatal lung infections in 48 of the 50 states and DC, including many regions previously thought to be safe from these pathogens. Some new research suggests this.
The prevalence of fungal lung infections was shown to be regional in the 1950s and 1960s. A new study, published on November 11 in the journal Clinical Infectious Diseases, indicates that this is no longer the case. The researchers warned that physicians using out-of-date maps of disease-causing fungi could overlook the symptoms of a fungal lung infection, leading to a delay or wrong diagnosis.
Histoplasma, or histo for short, is one of the three most common types of soil fungi responsible for triggering lung infections in Americans. Traditionally, the midwest and sections of the east were home to Histoplasma, the southwest to Coccidioides, and the south to Blastomyces. All three, however, have been shown to have spread outside their historical ranges in recent decades, with climate change likely being the driving factor.
Inhaling spores from soil fungi causes fungal lung infections in humans. When the ground is broken for whatever reason—farming, gardening, construction, or even just the passage of people in fungi-rich settings like caves—the spores are released into the air. While most healthy children and adults have no trouble fending off a fungal infection, the very young, the elderly, and those with impaired immune systems may experience fever, cough, lethargy, and other symptoms. It is not uncommon for COVID-19, bacterial pneumonia, and tuberculosis to be misdiagnosed as fungal lung infections.
Using Medicare fee-for-service records from all 50 states and DC, the study discovered the number of cases of fungal lung infections from 2007 to 2016. Patients’ county of residence was determined using their mailing addresses; the rate of new cases per 100,000 residents per year was then determined for each county. (Person-years are used to account for the vast demographic differences between counties; one Medicare recipient for one year equals one person-year.) Counties with a significant number of fungal lung infections were defined as those with at least 100 cases of Histoplasma or Coccidioides or 50 cases of Blastomyces per 100,000 person-years.
