A second person treated at Overlake Hospital Medical Center in September has tested positive for Legionnaires’ disease, though health officials said Friday that it’s not clear whether she acquired it at the facility.

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A second person treated at Overlake Hospital Medical Center in September has tested positive for Legionnaires’ disease, though health officials said Friday it’s not clear whether she acquired it at the facility.

The patient, a King County woman in her 50s, was treated in the Overlake emergency department Sept. 23 and was hospitalized with Legionnaires’ disease, a serious type of pneumonia, at a different hospital on Sept. 29, according to a blog posted by Public Health — Seattle & King County. She is recovering.

That’s three days after health officials reported that a man in his 60s had contracted Legionnaires’ disease at the hospital. He had a medical condition that made him susceptible to illness.

The woman may have been exposed in the community or in the hospital. Legionella bacteria are common in the environment.

However, preliminary environmental tests detected Legionella in one sink and an ice machine at Overlake, health officials said. Further test results are pending at the Centers for Disease Control and Prevention (CDC).

The Overlake cases follow an outbreak of Legionnaires’ disease at the University of Washington Medical Center that sickened five people in late August and September, including two who died.

The bacteria were detected in several sites in the hospital’s Cascade Tower. Officials installed special filters and flushed the tower’s water system with high doses of chlorine. Since those steps were taken at UW Medical Center, no new Legionnaires’ disease cases have been reported.

Because the period of time that has passed is more than twice as long as the typical incubation period of the infection, health officials said the UW Medicine outbreak may be over, though they’re continuing to monitor the situation.

There is no apparent connection between the Overlake cases and the outbreak at the UW Medical Center, health officials said.