Rare Brain Fungus Cases Surge Across U.S., Public Health Officials Urge Tracking
Cladophialophora bantiana, a fungus with a high fatality rate, is increasingly detected in healthy individuals.
A rare and aggressive fungal infection that can infect the brain, Cladophialophora bantiana (C. bantiana), has seen a nearly fourfold increase in detections across the United States, prompting public health officials to call for heightened awareness and national tracking.
The black yeast-like mold, which contains melanin, can cause severe brain abscesses and has a fatality rate of 60% to 70%, even with aggressive medical treatment, according to a report from the Centers for Disease Control and Prevention (CDC).
Data from a University of Washington laboratory indicates that the detection of C. bantiana surged from one to five cases per year between 2009 and 2023 to eight cases in 2024 and 14 cases in 2025. Researchers observed this trend despite comparing the number of infections to the total number of brain tissue samples tested for fungi, which rose from 8.4 cases per 1,000 specimens during 2017–2023 to 26 cases per 1,000 specimens in 2025.
"Reasons for the apparent increase are unknown," the CDC report stated, emphasizing the need for systematic national reporting mechanisms to better track the pathogen. Cases have been reported across 21 states and the District of Columbia, with California, Florida, Texas, and Pennsylvania reporting the highest counts.
Unlike many fungal infections that primarily affect immunocompromised individuals, about half of C. bantiana infections occur in otherwise healthy people. The fungus is believed to enter the body through inhalation or a skin wound, then travel to the brain through the bloodstream. The CDC report notes that 88% of detected cases were in brain tissue samples and 12% were in lung tissue, supporting the inhalation theory.
Diagnosing C. bantiana can be challenging as it often manifests as a brain abscess without clear external signs of infection. Standard tests like spinal taps may not detect the fungus, sometimes necessitating a surgical tissue sample for confirmation.
Public health experts advise clinicians to consider C. bantiana when evaluating patients showing signs of a brain abscess. Treatment typically involves surgical removal of infected tissue and a course of multiple antifungal medications.