MADISON, Wis. (CBSNews) -- Three patients who contracted Legionnaires' disease at the University of Wisconsin Hospital (UW Health) have died, CBS Madison affiliate WISC-TV reports.

The hospital said in a release Monday that the three had serious, life-limiting health conditions. Ten other patients who contracted the disease have been discharged and are doing well, according to UW Health.

The hospital has confirmed a total of 14 cases during the outbreak.

UW Health announced late last month that there were multiple cases of Legionnaires', a type of pneumonia caused by the legionella bacteria, and linked the outbreak to a change in its hot-water system.

The hospital flushed the system with high levels of chlorine to eliminate the bacteria. A week later, the hospital discovered the outbreak had affected 11 patients.

The hospital said Monday the strain of bacteria in the new cases of Legionnaires' matched the bacteria in the water system but that the hyperchlorination has been effective.

"Testing completed so far continues to show the expected reduction in the bacteria," the hospital said Monday. "UW Health will continue intensive monitoring of its water system to ensure patient safety."

The hospital said it's working with the federal Centers for Disease Control and Prevention to review and analyze its work in responding to the issue.