A deadly fungal mold that causes severe brain abscesses is surging in the United States. Doctors don’t know why. Health experts from the Centers for Disease Control and Prevention (CDC) and the University of Washington are raising alarms over a sharp rise in infections caused by Cladophialophora bantiana, a rare black mold that attacks the human central nervous system. Laboratory surveillance reveals that detected cases quadrupled between 2023 and 2025, spreading across at least 21 U.S. states. The pathogen primarily invades brain tissue, forming severe, pus-filled abscesses that cause devastating neurological damage. What makes the outbreak particularly troubling to researchers is that unlike most invasive fungal pathogens that target only vulnerable individuals, this fungus is infecting otherwise healthy people with fully functioning immune systems. Scientists remain baffled by the underlying cause of the surge, as there is currently no centralized federal tracking system specifically dedicated to monitoring the fungus. Researchers suspect spores are inhaled or introduced through minor skin wounds before traveling to the brain. With case-fatality rates reaching up to 70 percent even with aggressive surgical and antifungal treatments, epidemiologists emphasize the urgent need for heightened clinical awareness and expanded diagnostic testing. As changing environmental conditions potentially play a role in spore proliferation, medical professionals are urging hospitals nationwide to stay vigilant for unusual neurological symptoms. source: Lieberman, J., et al. (2026). Detection of Cladophialophora bantiana Infections — United States, 2009–2026. Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention.