In a surprising turn of events, a rare fungal infection, typically associated with the northern Midwest and parts of the Southeast, is now appearing more frequently in other regions of the United States, as revealed by recent research. The infection, known as blastomycosis, poses challenges for diagnosis due to its resemblance to other respiratory infections and becomes more challenging to treat the longer it goes undetected.
The culprit behind blastomycosis is the fungus Blastomyces dermatitidis, thriving in wet soil, decaying logs, and leaves. Designated as an "endemic mycosis," this fungal disease was traditionally confined to specific geographic areas like the Great Lakes, Ohio River valley, and Mississippi River valley. However, a new study published in the Centers for Disease Control and Prevention’s Emerging Infectious Diseases journal discloses cases of blastomycosis in Vermont, a region not commonly associated with the infection.
Dr. Arturo Casadevall, Chair of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, notes the unexpected emergence of blastomycosis in Vermont aligns with recent findings suggesting the nationwide movement of fungal infections. Dr. Brian Borah, the study's lead from the Chicago Department of Public Health, raises questions about whether the increased detection results from improved awareness or an actual rise in cases.
Fungal diseases, including blastomycosis, are underreported, making public surveillance crucial. Currently, only five states—Arkansas, Louisiana, Michigan, Minnesota, and Wisconsin—have surveillance for blastomycosis, leaving the prevalence outside these states unknown.
To uncover the extent of blastomycosis in Vermont, Borah's team analyzed health insurance claims from 2011 to 2020. The study identified 114 cases, with 30% requiring hospitalization. Vermont exhibited higher blastomycosis rates than most surveilled states, highlighting the unexpected nature of the infection's spread.
Factors contributing to the geographical expansion of fungal infections include travel, soil disturbances, and climate change. Blastomyces dermatitidis spores become airborne when disturbed, potentially reaching new areas. Climate change alters rain patterns, increasing humidity in some regions and causing soil redistribution, influencing fungal range.
Asiya Gusa, an assistant professor at Duke University, emphasizes the impact of climate change on fungal exposure, predicting a larger accumulation of spores with rising humidity and warm, damp weather. Early studies suggest climate-induced stress on fungi, potentially affecting their epidemiology.
Blastomycosis, triggered by inhaled spores, presents challenges in treatment due to the fungus morphing into resilient yeast cells. Fungal infections, often misdiagnosed and challenging to treat, are a concern for immunocompromised individuals. While blastomycosis usually occurs in healthy individuals, its similarity to other illnesses leads to delayed detection.
Dr. Bruce Klein of the University of Wisconsin-Madison underscores the difficulty in developing drugs targeting fungi without harming human cells. Though most blastomycosis cases are treatable, early detection remains crucial to prevent severe complications. The evolving landscape of fungal infections across the U.S. prompts a closer look at the intersection of climate change, human activity, and the epidemiology of these diseases.