A fungus that can cause fatal brain damage even in otherwise healthy people is spreading rapidly in the United States.
Cases Quadruple in Two Years
Researchers at the University of Washington and the Centers for Disease Control and Prevention said infections with Cladophialophora bantiana, a fungus that attacks brain tissue, have risen sharply in recent years, according to Britain's Daily Mail and other outlets on the 15th. The study was published in the CDC's Morbidity and Mortality Weekly Report.
From 2009 through 2023, the United States recorded one to five cases a year. The total rose to eight in 2024 and reached 14 in 2025. Cumulative cases from January 2009 through July of this year totaled 48. The death rate among those infected is reported at 60% to 70%.
Cases have been confirmed in 21 states and Washington, D.C. California reported the most with six, followed by Florida and Texas with five each and Pennsylvania with four. Patients had an average age of 68, and the infection involved brain tissue in 88% of cases and the lungs in 12%. Cases have also been reported in Canada, the United Kingdom, Japan, India, France, Belgium, South Africa, Mexico, Brazil and Malaysia.
Crossing the Blood-Brain Barrier to Form Abscesses
The fungus is dangerous because it can reach the brain after entering the body.
Once in the brain, the fungus can cause phaeohyphomycosis. The disease produces abscesses in which pus and necrotic tissue accumulate inside the brain, and inflammation and rising intracranial pressure can bring severe headaches, nausea and vomiting.
The reason for the sharp increase remains unclear. The researchers have raised the possibility that climate change has contributed to the spread. The CDC believes the fungus lives in soil in subtropical or humid regions and that infection can occur when it is inhaled. How exactly it enters the body, however, has not been confirmed.
The researchers said the fungus is rarely found in natural environments and that patients' exposure routes vary widely. Without a nationwide surveillance system, they said, it is difficult to identify where the fungus lives and how infections occur.
They urged clinicians to be aware of the rising trend and to watch patients closely for brain abscesses and related symptoms.