In a follow-up to an earlier report on the Legionnaires’ disease situation at the University of Washington Medical Center (UWMC), Public Health-Seattle and King County said Wednesday that the hospital reported a second fatality in a patient on the cardiac care unit in which Legionella, the bacterial cause of Legionnaires’ disease, may have been a contributing factor.

Legionella pneumophila bacteria/CDC
Legionella pneumophila bacteria/CDC

Health officials say the death happened on August 27, but the connection with Legionella was made at autopsy.

Three patients have tested positive for the bacterial pneumonia and two have died.

In addition, UWMC reported that environmental samples of their water supply in the Cascade Tower, which includes their cardiac care unit, tested positive for Legionella. They have taken immediate steps to reduce the risk where Legionella has been found in the water.

Legionnaires’ disease gained national notoriety in 1976 when the Centers for Disease Control and Prevention (CDC) discovered it during an epidemic of pneumonia among American legion members at a convention in Philadelphia.

The causative organism is the bacteria, Legionella pneumophila. Other species have also been implicated in Legionnaires’ disease. The legionella bacteria are found throughout nature, because of this most people become exposed to it but few develop symptoms.

The primary place in nature it’s found is water sources particularly at warmer temperatures; lakes, rivers and moist soil.

It is also found in man-made facilities (frequently the source of outbreaks) such as air-conditioning ducts and cooling towers, humidifiers, whirlpools and hospital equipment.

People get exposed through inhaling infectious aerosols from these water sources. There is no transmission from person to person.

The infection can appear in two clinical forms: Legionnaires’ disease and Pontiac fever.

Both conditions are typified by headache, fever, body aches and occasionally abdominal pain and diarrhea.

Legionnaires’ disease is the cause of pneumonia where a non-productive cough is typical. Fatality rates of this form of the infection are around 15 % even with improvements in treatment.

Pontiac fever is a self-limiting flu-like illness that does not progress to pneumonia or death. Diagnosis is usually made by typical symptoms in an outbreak setting.

Certain health conditions make you more susceptible to infection to include increasing age, smoking, chronic lung disease, malignancy and diabetes mellitus.

Legionnaires’ disease is treatable with antibiotics.

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.