Legionella, the bacterium that causes Legionnaire’s disease, was detected in several water sources at UW Medical Center. Five patients contracted the disease; two have died. The cases were isolated to the fifth floor of UWMC’s Cascade Tower. Hospital officials say the general public is not at risk.
Here’s what we know, based on information from UWMC, Public Health – Seattle King County, the CDC, and Jude Van Buren, senior director of UW’s Environmental Health & Safety.
What is Legionella?
It’s a type of bacteria that exists naturally in freshwater environments. But it grows best in warm and stagnant water, and can spread in man-made water systems such as hot tubs, hot water tanks, plumbing systems and air conditioning units for large buildings.
How does it spread?
By breathing in a mist or inhaling aerosolized water particles. Less commonly, it’s spread by aspirating water – when the water goes down the windpipe to your lungs. It does not normally spread from person to person.
Who’s susceptible?
You’re at higher risk if you’re over 50, have a weak or suppressed immune system, are a past or present smoker, or have a chronic lung disease. All five UW patients were in the higher-risk category. Most people don’t get sick after exposure.
What are symptoms of Legionnaires’ disease?
Coughing, shortness of breath, fever, headache and muscle aches. Lung infection can result in a serious type of pneumonia.
How common is it?
It’s quite rare, with about 5,000 cases reported annually.
What do we know about the UWMC cases?
The infected people were patients receiving treatment in cardiac-care units of the fifth floor of the Cascade Tower, on the east end of the hospital. They have been referred to as a “high-risk” group because of their health impairments. Officials said on Wed., Sept. 14, they had detected Legionella in several water sources within the Cascade Tower, including an ice machine, two sinks and three pieces of operating room equipment that don't come into direct contact with patients. The ice is not for human consumption.
What steps has the UWMC taken to protect patients and visitors?
They’ve limited water use on all inpatient care units in the Cascade Tower until special bacterial filters are installed for the showers and sinks. Until those filters are in place, people are asked to drink bottled water and to refrain from showering. Restrictions are clearly posted.
UWMC began treating water Mon., Sept. 19, in the Cascade Tower with a high dose of chlorine circulated through the water system and then flushed. Sufficient levels of chlorine prevent the spread of Legionella bacteria.
Is the water supply in Health Sciences at risk?
An update from UW Environmental Health and Safety (EH&S) reads: “Campus Engineering confirmed that the plumbing system serving UW Medical Center’s Cascade Tower (where Legionella bacteria was found) does not cross-connect to other plumbing systems in the UW Medical Center or Health Sciences Building. The UW receives its water from the City of Seattle, and after arrival in the Cascade Tower, backflow prevention and other devices prevent cross-connection to water systems in other areas.”
Will water sources be tested in the Health Sciences Building?
It takes a while to test for Legionella. Experts say it’s more efficient to check if the water system is sufficiently chlorinated. EH&S has received data from Seattle Public Utility and Campus Engineering that demonstrates chlorine levels in water at the Health Sciences Building are at an appropriate level.
Can I drink the water?
Yes. Environmental Health and Safety says it has no information that any water fountain within the Health Sciences complex is delivering water that is not meeting drinking water standards. Bottled drinking water is not necessary.
Here are some additional resources:
CDC page on Legionella: http://www.cdc.gov/legionella/about/index.html
UWMC press conference: https://www.periscope.tv/UWMedicine/1kvJpVkRkpaKE
UW Medical Center Legionella update: http://hsnewsbeat.uw.edu/story/uw-medical-center-legionella-update-9142016
UW Environmental Health & Safety update: https://www.ehs.washington.edu/pso/whatsnew.shtm