The Forest Hills Elementary School, which has 25 teachers and about 430 students in kindergarten through fifth grade in the Lake Oswego school district in Portland, will be closed through Wednesday for a "deep cleaning," the Oregonian newspaper said.
The Oregon health authority said a school employee, who was not identified for privacy protection, experienced COVID-19-like symptoms beginning Feb. 19 and had no history of traveling abroad nor close contact with any infected person.
The patient is now put under "appropriate isolation" and treated at Kaiser Permanente Westside Medical Center in Hillsboro, officials said.
The health department has alerted families that their children, together with school staff, could be exposed to risks of COVID-19.
"We are awaiting confirmation of the test results from the Centers for Disease Control and Prevention (CDC), but at this time we are considering this a presumptive case," said Oregon state health officer Dean Sidelinger.
Data from the CDC showed that the United States has a total of 15 confirmed COVID-19 cases, with three cases of person-to-person transmission. There are also 47 infected people who evacuated from either Wuhan, China, or the Diamond Princess cruise ship docked in Japan.