Disneyland shut down two cooling towers in October after people who visited the Southern California theme park were diagnosed with Legionnaires’ disease.

A dozen cases of the bacterial illness were discovered approximately three weeks ago, the Orange County Health Care Agency confirmed to The Associated Press. All the patients lived or had spent time in Anaheim and nine had visited Disneyland in September. One patient, who hadn't visited the park, has died.

Legionnaires’ can cause severe pneumonia. It is spread by mist from contaminated water.

Disneyland says it learned about the Legionnaires’ cases in late October and shut down and disinfected two cooling towers that tested for high levels of the bacteria. The towers will reopen once they are no longer contaminated, park officials said.

The health agency told The AP that no new cases have been reported.