LAKEWOOD, Wash. -- The Clover Park School District says Lakes High School in Lakewood is closed Friday after three students were hospitalized with flu-like symptoms. It's the sixth school in the Puget Sound area to close as a precaution against the spread of swine flu.

The other schools closed are:

- Madrona K-8 school in Seattle (through May 7)

- Odyssey Elementary school in Mukilteo (on Friday)

- Woodmont Elementary in Federal Way (through May 11)

- Aki Kurose Middle School (through May 7)

- Stevens Elementary School (through May 7)

Pierce County officials said Lakes High School was closed out of an abundance of precaution, and tests from those students have not been sent to the CDC because local tests have not yet ruled out a traditional flu strain.

Two students were listed in serious but stable condition at Madigan Army Medical, and the third student had already been released. Health officials said one of the students had a history of traveling to Mexico.

The other school closures were announced Thursday because they have a student with a probable case of swine flu - except Odyssey, where the student has a suspected case of swine flu.

"We thought this was an important precaution," Dr. Jeff Duchin of the health agency told a Thursday morning news conference outside the Madrona school.

The new King County swine flu cases include five more probable cases and two more suspected cases, said Dr. David Fleming, director of King County's Public Health office.

One of the Snohomish County flu victims - a 34-year Snohomish County woman - has a son with flu-like symptoms who attends Odyssey Elementary school in Mukilteo. Because of this, the boy has been labeled a "suspect" case.

The state Health Department is also tracking other children at the school. Depending on what they find, officials might recommend the school be closed longer than the one day.

In King County, health officials said four of the seven new cases involve children between the ages of 8 and 12. One is a woman in her 20s, and two more are the children of a 37-year-old pediatrician who works at the Everett Clinic in Mill Creek.

That doctor was one of the earlier announced probable cases. She is a pediatrician who saw 22 patients and their parents earlier this week before falling ill, officials at The Everett Clinic said Thursday.

The state Health Department cautioned that more probable cases of flu might be found in Washington as additional tests are conducted.

Officials were waiting for tests from the federal Centers for Disease Control and Prevention to confirm the probable cases are actually swine flu. But Dr. Gary Goldbaum, a health officer with the Snohomish Health District, said there's a 95 percent chance they are.

An 11-year-old student at the Madrona K-8 school had a cough and fever Monday and his mother kept him home, school officials said. He was later hospitalized and is recovering.

Duchin said no other cases had been found at Madrona.

Joan Rothrock, who volunteers once a week in a Madrona fourth-grade class, arrived at the school Thursday morning to find the doors closed and the school empty. "I think it's prudent. Better to be safe," she said.

Jon Hughes, vice president of Madrona K-8's PTSA, said his fifth-grade daughter has been in contact with the boy but he wasn't too worried.

"They all have lunch together and recess together, but she hasn't shown any symptoms," said Hughes, whose three kids attend the school. "As a parent, I was comfortable sending my kids back to school."

School district spokesman David Tucker said officials had planned to allow the school to remain open, but health investigators determined the infected boy may have been ill last Friday at the school.

State Health Department spokesman Tim Church said Thursday that it and the federal Centers for Disease Control and Prevention were continuing to test Washington samples for swine flu. The state is waiting for confirmation on the suspected cases from the CDC.

More than 100 samples have been sent so far to the state testing lab in Shoreline, officials said.

A 27-year-old Seattle man was also among the three suspected King County cases announced Wednesday night.

Two residents of Snohomish County are also probable to have swine flu. One case involves a 34-year-old Lynnwood woman, and the second is a 3-year-old Snohomish boy, said Dr. Gary Goldbaum with the Snohomish County Health District.

Goldbaum says the source of the Lynnwood woman's illness is a mystery as she has not traveled or been in contact with anyone who recently traveled. But he added he expects the virus to keep spreading.

"I expect the state is going to announce more cases every day from this point on for at least the next several days to weeks," he said.

The Department of Emergency Management in Snohomish County has set up a call center to address swine flu concerns. Residents can call (425) 388-5060 with question between 9 a.m. and 4 p.m. starting Friday.

A case in Spokane involves a man in his 40s who recently traveled to California, the Spokesman-Review reported. The man contacted health officials Thursday afternoon and has already mostly recovered and is no longer showing symptoms. He is related to a child in a local school, but that child has not shown any symptoms.

At this time, all schools and other public facilities in Spokane remain open. So far, cases have been mild.

Dr. Goldbaum said the concern over swine flu was great because the initial cases that developed in Mexico had a very high fatality rate.

But so far, most cases in the United States have been mild -- on par with the common variety influenza.

"What we're witnessing in this county appears to be a relatively milder form of influenza -- milder than what appeared in Mexico," he said. "The fact that it's sensitive to these anti-virals is great news, unlike the avian influenza where we're very concerned about (drug) resistance. This means we have treatment available. It appears at least in this country, most cases won't even require treatment and they will recover on their own."

But he stresses officials are keeping a high alert.

"It's just we don't know for sure and we don't understand why the cases in Mexico look different. And until we can be very clear on what happened in Mexico, we're treating this as potentially a much more severe disease than it may prove to be," he said.

Elsewhere in the region, health officials in Oregon reported the state's first probable case of swine flu Thursday in Multnomah County. Officials in Idaho reported one probable case in a Kootenai County woman. No confirmed cases had been reported in Alaska.

The Great Northwest Athletic Conference on Thursday night canceled this weekend's conference track and field championship meet in Monmouth, Ore., because of a probable single case of swine flu on the Western Oregon University campus, which will be closed at least through Monday.

Western Oregon also postponed a four-game baseball series this weekend at Central Washington University in Ellensburg, and a four-game softball series at Western Washington University in Bellingham.