A deadly fungus is spreading rapidly across the U.S., raising alarm among health experts as treatment options remain limited. According to the CDC, last year, the U.S. reported more than 4,200 confirmed clinical cases of C. auris. Unlike many other infections, some strains of C. auris are resistant to common antifungal medications, making treatment more difficult. Symptoms can be difficult to recognize because many people who develop C. auris infections are already dealing with other serious health conditions. While C. auris can be dangerous, experts say most healthy people are not at high risk.