SALEM, Ore. — Leaders of an American Indian reservation in Oregon shut down its casino and several other facilities Monday after an employee contracted coronavirus, and a state health official said the virus is likely circulating and will appear in additional locations in the state.

The employee of the Wildhorse Resort and Casino on the Confederated Tribes of the Umatilla Indian Reservation is hospitalized in Walla Walla, Washington, and is the third such case to emerge in Oregon, state and tribal officials said. The previous two other known cases occurred in the Portland area and had household contacts with each other, but the casino is 215 miles (350 kilometers) east of the city.

“With having three cases fairly quickly identified, two of which we can’t identify the specific source, that would indicate to us that this disease is circulating in our community and we will likely see additional cases,” Dean Sidelinger, state health officer and state epidemiologist, told The Associated Press in a telephone interview.

Meanwhile, dozens of employees of a hospital in a Portland suburb — Kaiser Permanente Westside Medical Center — have been quarantined at home after they may have had contact, unprotected, with the first Oregonian to come down with the virus, The Oregonian newspaper reported.

“Per current CDC guidelines, people who have had contact with COVID-19 patients are asked to maintain self-isolation at home for 14 days,” said Dr. Mary E. Giswold, associate director of Kaiser’s hospital and post-acute care.