In a follow-up to the Legionnaires’ disease situation at Seattle’s University of Washington Medical Center (UWMC), hospital officials have reported a fourth case of the bacterial infection.


Public Health – Seattle & King County says they were notified of the case on Friday. The patient, a forty-something male non-resident, was also hospitalized in the Cascade Tower where environmental tests have found Legionella; the patient’s exposure would have been prior to the identification of the bacteria, before protective measures were put in place.

The patient is currently in satisfactory condition. Officials say he is at increased risk for infection due to an underlying medical condition.

Legionellosis is a bacterial disease of the lungs caused by Legionella pneumophila. The disease can range from a mild respiratory illness to severe pneumonia and death. The most common form of legionellosis is known as “Legionnaires’ disease,” named after an outbreak in 1976 when many people who attended an American Legion conference in Philadelphia became ill.

Most people contract the disease by inhaling mist or vapor from a water source contaminated with the bacteria.   The disease is not contracted by drinking contaminated water, and person-to-person spread of legionellosis does not occur.

People of any age may get Legionnaires’ disease, but the disease most often affects persons older than 50.  The disease is rare in people younger than 20 years of age.  People at high-risk of acquiring the disease include current and former smokers, persons with chronic lung disease like emphysema or COPD, or those with compromised immunity (like patients who receive corticosteroids or have had an organ transplant).  People with underlying illnesses, such as cancer, kidney disease, diabetes, or AIDS are also at higher risk.

According to the Centers for Disease Control and Prevention (CDC), it is estimated that between 8,000 and 18,000 people are hospitalized with legionellosis in the United States each year.