Legionnaires' Disease

Legionnaires' disease (LEE-juh-nares) is caused by a type of bacteria called Legionella. The bacteria got its name in 1976, when many people who went to a Philadelphia convention of the American Legion suffered from an outbreak of this disease, a type of pneumonia (lung infection). Although this type of bacteria was around before 1976, more illness from Legionnaires' disease is being detected now. This is because we are now looking for this disease whenever a patient has pneumonia. Each year, between 8,000 and 18,000 people are hospitalized with Legionnaires' disease in the U.S. However, many infections are not diagnosed or reported, so this number may be higher. More illness is usually found in the summer and early fall, but it can happen any time of year.

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2017 Legionella Outbreak Information

Orange County Health Care Agency, with the support of the California Department of Public Health and the US Centers for Disease Control and Prevention, is investigating a cluster of Legionellosis cases among people who travelled to, worked in or lived in Anaheim during September and October 2017.  (See case count information below.) As part of the investigation, Disneyland Resorts identified two cooling towers in Disneyland that - through routine maintenance - were identified as having disease-causing levels of Legionella bacteria and treated in early October and tested negative for Legionella in early November. HCA’s investigation is continuing to rule out any ongoing risk to the public.  At this time there is no known ongoing risk for Legionella exposure associated with this outbreak.

Age Range Confirmed Cases Hospitalizations Deaths
52 to 94 16 14 2
Case counts are as of 11/17/2017