Of those cases, nine had visited the theme park in September. The Anaheim-based theme park has closed two of its cooling towers in response to the outbreak.
One of the three cases of the respiratory illness not linked to Disneyland was fatal in an individual who had additional health issues, said Jessica Good of the Orange County Health Care Agency. Walt Disney Parks and Resorts' chief medical officer, Dr. Pamela Hymel, confirmed that she had been contacted by officials regarding the park's alleged role.
The Orange County Register also revealed that the Centers for Disease Control and Prevention, the main national public health center of the United States estimated that the disease has been reported in 6000 cases in 2015 nationwide.
"We conducted a review and learned that two cooling towers had elevated levels of Legionella bacteria", she said. As a result, the county health care agency has determined that there is no longer a risk for infection at the Anaheim Disney park or at surrounding locations.
Good said an investigation of Legionnaires cluster discovered that the 12 people sickened by the serious lung disease had traveled to, lived in, or worked in Anaheim during the month of September.
It is typically contracted by breathing mist from the water that contains legionella bacteria.
Those two towers have since been treated with Legionella-destroying chemicals.
Legionnaires disease is a severe form of pneumonia caused by Legionella bacteria, sometimes found in water systems. The source of the mist can be air conditioning units in large facilities, showers or hot tubs.
The disease is not contagious.
According to OCHA spokeswoman Good, the two affected Disneyland towers were put back into service on November 5th, but then shut down again. The towers were taken out of service November 1, disinfected, went back in operation on November 5 but were shut down again Tuesday and will remain offline until tests confirm they are free from contamination, according to the park and the county health agency.