Rare Brain Fungal Infections Surge Dramatically, Prompting CDC Alert
Cases of Cladophialophora bantiana, a deadly fungal infection that typically attacks the brain, increased approximately fourfold between 2023 and 2025 according to a U.S. clinical laboratory, though the cause of this rise remains unclear. The infection, which presents as brain abscesses in 88% of cases, carries a fatality rate as high as 70% and is striking otherwise healthy individuals. Researchers noted the alarming nature of these infections occurring outside typical high-risk populations, with cases distributed across 21 states.
The infection caused by Cladophialophora bantiana typically enters the body through inhalation or skin injuries, then spreads to the brain where it forms abscess lesions in the majority of affected individuals. Detection rates have accelerated dramatically at the University of Washington's reference laboratory, which analyzes specimens from across the country—jumping from single-digit annual cases historically to 14 confirmed infections in 2025 alone.
Researchers acknowledge significant uncertainty about the actual scope of disease. The observed increase may partly reflect improved molecular diagnostic techniques and greater sample submission, but alternative explanations include environmental factors. Climate change and rising temperatures could enable fungal adaptation to human hosts, while expanding human activity in natural environments might increase exposure to the organism's reservoir.
The surge could prompt changes in how clinicians evaluate unexplained brain infections, particularly in patients without obvious immune compromise. Increased awareness may lead to more diagnoses and treatment attempts, though the infection's high fatality rate and rarity mean it will likely affect relatively few patients. Public health agencies and laboratory networks may need to coordinate surveillance efforts to clarify whether this represents a genuine emerging threat or improved detection of an existing disease.