A rare black mold that invades the brain and kills up to 7 in 10 patients is climbing fast across the country, and federal health officials say they still cannot explain the rise.
Federal data now show a sharp jump in detections of Cladophialophora bantiana, a black yeast-like mold that can reach the brain and trigger a severe infection. Fox News Digital reported the findings from a Centers for Disease Control and Prevention review tied to laboratory work at the University of Washington.
From January 2009 through July 2026, researchers identified 48 confirmed cases and one probable case in tissue samples drawn from 21 states and the District of Columbia. Annual counts hit eight in 2024 and 14 in 2025. That is a steep climb from the one-to-five cases a year the University of Washington microbiology laboratory typically saw between 2009 and 2023.
Detection rates tell the same story. The lab recorded 8.4 cases per 1,000 specimens from 2017 through 2023. In 2025 the figure reached 26 cases per 1,000 specimens. Detections nearly quadrupled between 2023 and 2025.
The median patient age was 68. About half of the infections struck people who were otherwise healthy. California logged the most cases with six, followed by Florida and Texas with five each and Pennsylvania with four.
Eighty-eight percent of the detections came from brain tissue. Twelve percent came from lung tissue. Researchers believe the mold can enter through inhalation or a skin wound, then travel through the bloodstream to the brain. The tissue pattern fits that pathway.
A systematic review published in the journal Medical Mycology linked the fungus to a 60% to 70% fatality rate even when doctors move fast with surgery and multiple antifungal drugs. Diagnosis is not simple. It may require a surgical tissue sample. In one fatal case at University of Washington Medical Center, spinal fluid PCR tests came back negative both a month before a brain biopsy and at the time of the biopsy.
Public health officials are urging clinicians to consider fungal pathogens when they evaluate brain abscesses. The CDC report also calls for systematic national reporting so the country can track the pathogen with more precision than scattered lab catches allow.
On the central question, why the jump now, the agency is blunt.
"Reasons for the apparent increase are unknown"
That is the full official answer. No clear environmental driver. No settled clinical explanation. No finished national case system already in place, only a call to build one.
C. bantiana contains a dark pigment called melanin and behaves like a black yeast-like mold. Once it reaches the brain, the infection is aggressive. Treatment pairs surgery with several antifungals, yet most patients still die. Negative spinal fluid tests can lull teams into a false sense of security until tissue is taken and examined.
The practical message from public health experts is straightforward: when a patient shows signs of a brain abscess, doctors should put this fungus on the list, not treat it as a medical footnote. Heightened awareness is the near-term tool while national tracking remains incomplete.
Cases have now turned up across a wide geographic band, not a single hot zone. The highest counts sit in large, warm-weather and high-population states, but the 21-state footprint shows the organism is not confined to one region. For a pathogen this lethal, sparse reporting is a problem in itself.
Americans expect public health agencies to spot deadly threats early, explain what is driving them, and give front-line doctors clean guidance. A mold that kills most of its patients is rising in lab detections, the fatality rate is already known, and the stated reason for the surge is still a blank line. That gap belongs on the accountability ledger.
