Oregon’s third presumptive coronavirus case is a casino worker who attended a youth basketball game at a Umatilla County middle school, authorities announced Monday as one of the state’s top health officials said he expects more cases to develop, including ones that could prove fatal.

Dr. Dean Sidelinger, the state’s health officer, said the virus will continue to spread in Oregon but that the health system is prepared for the disease.

“We know that people are scared,” he said. “We are learning more and more about this disease every day.”

Of the three Oregon patients, one has mild symptoms but the Oregon Health Authority has declined to give out the conditions of the other two, who are receiving hospital treatment.

Sidelinger continued to urge calm and advise regular hand-washing, even as the epidemiologist acknowledged that having multiple cases of unknown origin in the state could mean that the coronavirus is “fairly widespread in our community."

But the majority of people who get sick worldwide have a mild course of the disease, Sidelinger said, and those who need to be hospitalized usually have underlying symptoms.

Health officials currently are monitoring 101 Oregonians for symptoms because of their travel patterns or their contact with people known to have COVID-19. They will be tested for the disease only if they develop symptoms within 14 days their last potential exposure.

The man from Umatilla County with coronavirus was taken Saturday from the basketball game at Weston Middle School in Weston, a tiny town near the Oregon-Washington border, to a hospital in Walla Walla, Wash., officials said.

The school gym is closed for a deep cleaning, the state said. The gym is detached from the main school building. Weston Middle School enrolls 250 students in grades four through eight.

People who attended the game have a low risk of exposure to the virus and there is no risk of exposure at the main school, state health officials said.

The Governor’s Office told the Confederated Tribes of Umatilla Indian Reservation that a Wildhorse Resort and Casino employee had tested positive for the coronavirus, tribal officials said Monday. The tribes’ board of trustees ordered closed Nixyaawii Community School in Pendleton, as well as Head Start, a daycare and a senior center to sanitize the buildings. The casino, on the tribes’ reservation east of Pendleton, is also closed at least until it’s sanitized.

The casino employee with coronavirus is the same person who attended the youth basketball game.

Chuck Sams, a tribal spokesman, said the man worked in a secure area of the casino and was not exposed to patrons, numbering about 4,200 a day. The reservation is home to about 3,000 residents; he said about 30,000 people live in the surrounding 50-mile radius.

“The information just went out” this morning, Sams said. “The community is very concerned.”

Saturday’s basketball tournament at Weston Middle School was part of a recreational league for girls in grades four through six that featured a team from Weston as well as teams from Helix, Heppner and other Umatilla County towns.

The games drew primarily the players and their family members, said Athena-Weston Superintendent Laure Quaresma.

Quaresma said no students in her district’s schools have shown signs of the illness and the schools haven’t done anything new apart from reminding employees, students and parents of the symptoms to watch for and the best tools, including hand-washing, to prevent illness.

The health authority is working with Umatilla County and Washington state to trace people the patient may have had contact with after symptoms first appeared, state spokesman Robb Cowie said. The agency will announce other potential exposure sites if it finds any.

Oregon residents who attended Saturday’s game can call 211 if they have questions, Washington state residents can call 800-525-0127 and Walla Walla County residents can call 509-524-2637.

Washington’s public health laboratory did the test for COVID-19 on the new Oregon patient, who was one of state’s pending cases. The person is now at Providence St. Mary Medical Center. Cowie did not release the person’s condition or age.

This patient’s case is unrelated to the two others in Oregon, and the state is treating it as a “community transmission,” meaning health officials don’t know how the person became infected.

The new case is Oregon’s second that is unrelated to travel or contact with a person known to be sick. Cases of unknown origin create the risk that other people could be infected and not know it, potentially exposing others to an infection.

The Northwest outbreak and officials’ reaction to it are escalating rapidly. The country’s first six coronavirus deaths were reported in Washington over the weekend and into Monday, when four new deaths were announced. King County is planning to buy a hotel to house patients that will be available by the end of the week, County Executive Dow Constantine said at a Monday press conference.

“We have moved to a new stage,” Constantine said.

Oregon’s new case indicates a substantial geographic spread to the disease within the state.

The state’s two other cases are Washington County adults -- the first presumptive COVID-19 patient lives in Washington County but works at Forest Hills Elementary School in Lake Oswego in Clackamas County and the second patient is a “household contact” -- a family member -- of the first one.

The first patient was isolated in the hospital and the person didn’t need medical attention and was isolated at home, the Oregon Health Authority said. Rick Shidaker, executive director of the Oregon School Employees Association, said his union was told by the patient’s colleagues that the patient was a male custodian. Shidaker said he had not spoken directly with the man.

Clackamas County on Monday declared a state of emergency as a precaution, allowing it to access state resources, said county spokesman Tim Heider. “There is no public health emergency,” he said. “This is just a vehicle to provide that additional assistance.”

The declaration also doesn’t change the status of Lake Oswego schools, said district spokeswoman Mary Kay Larson. The district has closed the 430-student Forest Hills Elementary through Wednesday for cleaning and to allow a two-week coronavirus incubation period to run its course from the last time, Feb. 19, the infected employee was at the kindergarten-through-fifth-grade school.

New diagnoses in several states pushed the tally of COVID-19 cases past 100, and New Hampshire reported its first case, raising the total of affected states to 11.

CORONAVIRUS IN OREGON: FULL COVERAGE

Oregon currently has about 1,500 coronavirus tests available, although people might require more than one. If necessary, the state can get more tests from the U.S. Centers for Disease Control and Prevention, if necessary.

There have been nearly 90,000 confirmed cases internationally as of Monday morning.

The vast majority of them are in mainland China, where more than 80,000 cases have been confirmed and over 2,900 have died.

The total number of deaths from the virus has surpassed 3,000. South Korea, Italy and Iran have seen expanding clusters of infections.

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Staff writers Molly Young, Everton Bailey, Betsy Hammond, Brad Schmidt, Noelle Crombie, Jim Ryan, Jayati Ramakrishnan and Kale Williams contributed to this report.

-- Fedor Zarkhin

fzarkhin@oregonian.com

desk: 503-294-7674|cell: 971-373-2905|@fedorzarkhin

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