Three patients at the University of Washington Medical Center have been diagnosed with Legionnaire’s disease this week. One of them died Friday and now officials are investigating the hospital.

Legionella is the water-borne bacteria that causes Legionnaires’ disease: a severe pneumonia that can cause fever, shortness of breath or muscle aches.

But Dr. Jeff Duchin with Seattle & King County Public Health doesn't want to scare anyone.

“I wanted to emphasize that this situation does not represent a risk to the general public,” Duchin said. “The disease rarely, if ever, spreads from person to person.”

So how does someone even get it? Duchin said it can be contracted by breathing in mist contaminated with the bacteria.