New cases of Legionnaires’ Disease at Local Hospital

The University of Washington Medical Center (UWMC) has notified Public Health – Seattle & King County of two patients who were diagnosed with a serious type of pneumonia called Legionnaires’ disease caused by infection with Legionella bacteria.  The patients’ medical histories suggest that exposure to Legionella happened while hospitalized at UWMC.

The first patient, a male in his 40’s, was reported to Public Health on August 23, and is in the process of being discharged from the hospital. The second, a female in her 20’s, was reported to Public Health on August 24 and died on August 25. She was very ill, had multiple underlying conditions, and it is not yet known whether Legionella was a cause of death.  A third patient, a male in his 60’s who was also reported to Public Health on August 24 by UWMC, was diagnosed with Legionella pneumonia, but appears to have acquired the infection in the community and not at UWMC. He remains hospitalized.

At this time there is no evidence to suggest risk to the public or patients outside of the UWMC.

Public Health is in the early phase of our investigation. We are working closely with UWMC to determine if other patients may have been infected, to identify a potential source of the infections, and to address any ongoing risk.

UWMC has taken immediate measures to protect patients, visitors and employees by limiting exposure to water sources, including tap and shower water, while they investigate the source.  UWMC has also notified patients and staff of the situation.  At this time, no additional cases of Legionella have been identified at UWMC.

About Legionella

Legionella is a type of bacterium found naturally in freshwater environments, like lakes and streams, and grows best in warm water. It can become a health concern when it grows and spreads in human-made water systems like hot tubs, hot water tanks and heaters, decorative fountains, cooling towers (such as those used in air conditioning systems), and large plumbing systems.

Legionnaires’ disease, a type of
severe pneumonia, is caused by
breathing in small droplets of
water that contain Legionella. Images: CDC

People can become infected with Legionella when they breathe in a mist that is contaminated with the bacteria. A Legionella infection can turn into illness affecting the lungs, and in some cases, it can cause Legionnaires’ disease. Cases of Legionella typically occur 2-10 days after exposure to the bacteria.  In general, people do not spread Legionnaires’ disease to other people, although possible in rare cases.

Legionnaire’s disease is serious, but it can be treated with antibiotics. Most people who get sick need care in a hospital but make a full recovery. However, about 1 out of 10 people who get Legionnaires’ disease will die from the infection.

Who is at higher risk of getting sick?

Most healthy people do not get sick after being exposed to Legionella. People at increased risk of getting sick are:

  • People 50 years or older
  • Current or former smokers
  • People with a chronic lung disease (like chronic obstructive pulmonary disease or emphysema)
  • People with a weak immune system from diseases like cancer, diabetes, or kidney failure
  • People who take medications that suppress (weaken) the immune system (like after a transplant operation or chemotherapy)


Public Health – Seattle & King County’s role in the investigation

Investigation of infectious diseases is part of the essential work of Public Health – Seattle & King County. In this incident, our role is to assist with the investigation and assessment of the extent of the problem, identification of a source of the Legionella, and eliminate ongoing risk at the healthcare facility. We also provide information to the public about Legionnaire’s disease and on the findings and status of our investigation.

See more information from the CDC on Legionella.

Originally posted on August 25, 2017. Updates will be posted to this blog as they become available.

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