The fungus that infects the brain, which can kill 7 out of 10 patients, is on the rise across America

Cladophialophora bantiana, a neurotropic black mold with a mortality rate of 60 to 70 percent, nearly quadrupled in U.S. detections between 2023 and 2025.

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A rare fungal infection that can harm healthy people is on the rise across the United States, and public health officials are calling for increased awareness and national tracking.

Cladophialophora bantiana (C. bantiana) is a black yeast-like mold that can infect the brain and contains a dark pigment called melanin, according to a new report from the Centers for Disease Control and Prevention.

Data from a microbiology lab at the University of Washington shows that detections of the fungus will nearly quadruple between 2023 and 2025.

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Between January 2009 and July 2026, researchers identified 48 confirmed and one probable case of C. bantiana in tissue samples from 21 states and the District of Columbia. The average age of the patient was 68 years.

Unlike many fungal infections that mainly affect people with weakened immune systems, about half of C. bantiana infections occur in healthy people.

Cladophialophora bantiana (C. bantiana) is a black yeast-like mold that can infect the brain and contains a dark pigment called melanin, according to the CDC. (iStock)

Researchers believe that mold enters the body when inhaled or through a skin wound, then reaches the brain through the bloodstream.

The CDC report states that 88% of cases were detected in brain tissue samples and 12% in lung tissue, supporting the theory that respiratory inhalation is one of the primary mechanisms of transmission.

According to a systematic review published in Mycology Medicine, this fungus causes severe infection with a mortality rate of 60 to 70 percent, even with aggressive medical intervention.

The pathogen has historically been rare, with a University of Washington laboratory detecting only one to five cases per year between 2009 and 2023.

To make sure the increase wasn't simply due to more testing, the researchers compared the number of infections to the total number of brain tissue samples tested for fungi.

They found that diagnosis increased from 8.4 cases per 1,000 samples during 2017-2023 to 26 cases per 1,000 samples in 2025.

"The reasons for the apparent increase are unknown," states the CDC report, which calls for systematic national reporting mechanisms to better track the pathogen.

Cases have been reported over a wide geographic range, with the highest numbers in California (6), Florida (five), Texas (five) and Pennsylvania (4).

Standard tests such as spinal taps may miss the fungus, meaning doctors sometimes need to surgically take tissue samples to confirm the diagnosis. (iStock)

Because C. bantiana usually presents as a brain abscess without obvious external signs of infection, experts say early diagnosis is challenging.

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In a fatal case reported at the University of Washington Medical Center, CSF PCR tests showed negative results both a month before and at the time of brain biopsy, highlighting the difficulty in diagnosing the mold.

Public health experts recommend that physicians consider C. bantiana when evaluating patients with symptoms of brain abscess.

Treatment usually involves surgery to remove the infected tissue along with multiple antifungal medications.

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