A staffer for Sen. Maria Cantwell (D-WA) has come down with COVID-19, Cantwell’s office announced late Wednesday night, marking the first case of the coronavirus on Capitol Hill.

“The individual has been isolation since starting to have symptoms,” Cantwell’s office said in a statement. “On the advice of the Attending Physical, the senator has closed her Washington, D.C. office this week for deep cleaning and staff will be teleworking.”

The office stated that the staff member “has had no known contact with the senator or other members of Congress.”

Several congressional lawmakers have had to self-quarantine after making contact with individuals who later tested positive for the virus, but none of the lawmakers have shown symptoms.

The Capitol is poised to stop all public tours for the rest of the month. Congress has not announced any changes to its legislative schedule as of yet.

President Donald Trump has not declared a state of emergency over the rapidly growing outbreak, reportedly because he fears doing so would disprove his repeated claim that the coronavirus isn’t any more serious than the flu.