Cases of Candida auris, a fungus found in healthcare facilities, are rising rapidly this year, the US Centers for Disease Control and Prevention says.

As of July 25, 3,437 clinical cases in 27 states have been reported, CDC data shows. The agency recorded 4,290 clinical cases in all of last year.

C. auris is primarily a concern for people who are hospitalized. The total number of clinical cases has been increasing since its detection in the US in 2016, the CDC says. The rate has slowed in recent years, but it still remains a “critical public health threat.”

What is Candida auris, and how does it spread?

Candida auris is a yeast, a specific type of fungus, that spreads through contact with contaminated objects and people, according to Dr. Graham Snyder, medical director of infection prevention and hospital epidemiology at University of Pittsburgh Medical Center.