While U.S. residents have been focused on the measles epidemic and surviving flu season, a new, drug-resistant “superbug” has quietly spread throughout the country, infecting as many as 600 people in recent years.

Called Candida auris, the fungus is known to prey on people with weakened immune systems, the Centers for Disease Control and Prevention revealed Monday. While confirmed cases have only turned up in New York, New Jersey and Illinois (Chicago), researchers say they can’t be sure if the potentially fatal illness has spread beyond those states because it’s very difficult to detect.

People who recently had surgery, live in nursing homes, or who have breathing tubes, feeding tubes or central venous catheters appear to be at highest risk.

“Based on information from a limited number of patients, 30 to 60 percent of people with C. auris infections have died,” according to the CDC, which added people recovery from surgery, undergoing prolonged treated and the elderly are at the highest risk of contracting the fungus.

Does the idea of a new drug-resistant fungus scare you? Do you think civilization will ever be illness-free?