(NEXSTAR) – Health care facilities around the country have been put on alert by the Centers for Disease Control and Prevention and told to look out for signs of Candida auris, or C. auris, a fungus that can be deadly if it enters a patient’s bloodstream.

The fungus has already been detected in more than half of U.S. states and is spreading at an “alarming” rate, the CDC says.

Candida auris, which mainly spreads in health care settings like hospitals or nursing homes, can cause serious and invasive infections, according to the CDC.

The fungus is especially dangerous because it is resistant to antifungal drugs, making it hard to treat.

“If you get infected with this pathogen that’s resistant to any treatment, there’s no treatment we can give you to help combat it. You’re all on your own,” Melissa Nolan, an assistant professor of epidemiology and biostatistics at the University of South Carolina, said.

That means it’s up to your immune system to fight off the infection. Someone with a healthy immune system will have an easier time beating back Candida auris than someone who is immunocompromised. Unfortunately, the pathogen is most likely to spread to people with compromised immune systems because it often enters the body through invasive medical devices like catheters or PICC lines.

The CDC estimates that “based on information from a limited number of patients, 30–60% of people with C. auris infections have died. However, many of these people had other serious illnesses that also increased their risk of death.”

Another reason Candida auris is so concerning is because of how well it has adapted to surviving on surfaces, Nolan said.

“It’s really good at just being, generally speaking, in the environment,” Nolan explained. “So if you have it on a patient’s bed for example, on the railing, and you go to wipe everything down, if in whatever way maybe a couple of pathogens didn’t get cleared, then they’re becoming resistant. And so over time, they can kind of grow and populate in that hospital environment.”

Because it has evolved to survive that sort of routine hospital disinfectant, the CDC considers Candida auris an “urgent antimicrobial resistance (AR) threat.”

Another reason Candida auris is so dangerous is it can be hard to identify with standard lab tests, making it even more difficult to treat properly and early.

“The rapid rise and geographic spread of cases is concerning and emphasizes the need for continued surveillance, expanded lab capacity, quicker diagnostic tests, and adherence to proven infection prevention and control,” CDC epidemiologist Dr. Meghan Lyman said in a press release.

“I think we need to do a better job of predicting,” Nolan said. “Moving forward [we need] more funding to support quality surveillance of these potential infectious strains so that we can know in advance, and we can do a better job of stopping disease spread before it becomes a problem.”