SEATTLE — Washington state reported a total of nine coronavirus deaths Tuesday as schools in the Seattle area mulled teaching students online in the event of prolonged closures over health concerns.

The schools took the steps after researchers said the virus that causes the disease called COVID-19 may have been circulating for weeks undetected in the state, and experts said more cases will probably be reported soon.

The Washington state Department of Health says there are 27 confirmed cases, all in the Seattle area. The nine cases include four tied to a suburban Seattle care facility that has reported multiple virus cases and deaths.

Health officials in North Carolina reported Tuesday that a person from Wake County tested positive for the illness after visiting the long-term care facility in Kirkland, Washington, where many of the state’s cases originated. The person is in isolation and is doing well, according to the North Carolina health department.

Among the newly reported deaths was a man in his 50s who had been a resident of Life Care Center in Kirkland, who died at Harborview Medical Center in Seattle Feb. 26. Tests later determined he died of COVID-19. Hospital spokeswoman Susan Gregg said some hospital staff may have been exposed while treating the patient but official don’t believe other patients were exposed. The hospital staff are being monitored and screened daily.