BOTHELL — Tests were still pending Friday on the family member of a Bothell High School staffer whose mysterious illness led officials to keep the campus closed for a second day.

District leaders closed the school Thursday out of an abundance of caution, and it was not clear when classes would resume.

“I do not make this decision lightly,” Northshore School District Superintendent Michelle Reid wrote Thursday night in a letter to families.

“We recognize that Public Health Seattle-King County did not recommend closing Bothell High School as they believed the risk of the coronavirus exposure to students and staff is low,” Reid wrote. “They shared with me that in the end, it was my call. Because I heard ‘low risk’ and not ‘no risk,’ I feel it is my responsibility to extend the closure through Friday.”

The family member of the school employee came down with an undiagnosed illness after international travel.

At the time, it was not a confirmed case of the new Wuhan coronavirus, known as COVID-19, but the school closed so classrooms could be disinfected.

The staff member, who returned to work Monday when school resumed after a mid-winter break, was not ill and was not tested for coronavirus.

Officials in a neighboring school district prematurely and erroneously notified staff Thursday afternoon that the tests came back negative — but as of hours later, the tests still weren’t complete, a spokeswoman at the Snohomish Health District said.

The worker’s family member became sick on Tuesday “and was taken to the hospital, and is currently being treated, monitored and quarantined,” Reid wrote late Wednesday. The staff member was expected to be quarantined at home for 14 days.

She added: “There is no confirmation that the family member’s illness is connected to the coronavirus outbreak, but out of an abundance of caution, the family member is being tested.”

The halls inside Bothell High School, closed for the day, stand empty Thursday. (AP Photo/Elaine Thompson)

According to the Washington State Department of Health website, results are pending on four coronavirus tests statewide. Another 322 people are under public health supervision for possible exposure.

Testing is about to get much faster.

Past tests have been sent to the Centers for Disease Control and Prevention in Atlanta, with results taking five to seven days. Starting this week, virus testing will be conducted at the state Department of Health Public Health Laboratories in Shoreline, producing much faster results, health officials said at a Thursday press conference.

The Washington lab will start out doing up to 26 tests per day, six days a week.

“The goal is if it’s in here in the morning we will have a result by 5 o’clock that afternoon,” state health epidemiologist Dr. Scott Lindquist said. “It’s a lot quicker.”

Dr. Kathy Lofy, state health officer, said Washington is in “the containment phase” to keep the virus at bay and from spreading.

“The risk is considered low,” Lofy said.

She advised people should prepare for a possible spread in the future. This includes measures such as closing schools, canceling large public events and encouraging employers to let people work from home.

“There really is no need to panic,” Lofy said.

Areas where the Bothell High staff member went on the campus at 9130 NE 180th St. were disinfected Wednesday, and the entire school was then being disinfected as a preventive measure.

Friday’s school closure “will provide us an opportunity to complete the cleaning and hopefully receive the results of the test,” Reid wrote in the email. ”All evening activities on the school campus are cancelled. Our staff across the district are working to move or reschedule those activities. Also, we will make a decision on weekend activities as soon as possible on Friday.”

Northshore covers portions of both King and Snohomish counties. Other schools in the district remained open this week.

“The most important thing our residents and businesses can do is remain calm, prepared, and informed,” said Heather Thomas, spokeswoman for the Snohomish Health District. “We encourage the community to monitor reliable news sources and the Snohomish Health District website for updates on this fluid situation.”

There has been one confirmed case of coronavirus in Washington. The man, who was the first in the U.S. to test positive for the virus, was treated at Providence Regional Medical Center Everett. The Snohomish Health District released the patient from home isolation last week and said he is considered fully recovered.

In developments worldwide:

• The Dow Jones Industrial Average sank nearly 1,200 points Thursday, deepening a week-long global market rout caused by worries that the coronavirus outbreak will wreak havoc on the global economy.

• A new coronavirus case in California could be the first in the U.S. that has no known connection to travel abroad or another known case. All of the 59 other cases in the U.S. had traveled from abroad or had been in close contact with those who traveled.

• President Donald Trump is under fire for the government’s response to the crisis. He’s voiced his unhappiness at how concerns over the virus’ spread has hit the stock market hard. But given how acute the concerns are, Trump has sought to defend his administration’s record as the number of cases in the U.S. are expected to pick up. He has put Vice President Mike Pence in charge of coordinating the efforts. That hasn’t made everyone happy, nor has it calmed the mood. Health officials stressed that schools, businesses and individuals need to get ready.

• Japan Prime Minister Shinzo Abe says he wants all elementary, middle and high schools nationwide to remain closed until spring holidays in late March. Japan now has more than 900 cases.

The Associated Press contributed.

A school janitor opens the door to a staff room inside Bothell High School, which was closed for the day, on Thursday. The school was closed after a staffer’s family member was placed in quarantine for showing symptoms of possibly contracting coronavirus. (Elaine Thompson / Associated Press)

A school janitor opens the door to a staff room inside Bothell High School, which was closed for the day, on Thursday. The school was closed after a staffer’s family member was placed in quarantine for showing symptoms of possibly contracting coronavirus. (Elaine Thompson / Associated Press)