EMBED >More News Videos A case of coronavirus has been diagnosed in an evacuee from China housed at a San Diego base, the first confirmed case among hundreds of American evacuees.

LOS ANGELES (KABC) -- The Los Angeles County Department of Public Health is monitoring about a thousand people who recently traveled to China, regardless of whether they've shown symptoms for coronavirus.They've all been assigned a nurse and have been told to quarantine themselves at home for 14 days as a precaution.Meanwhile, 195 Americans evacuated from China have been cleared to leave March Air Reserve Base in Riverside after clearing their final screening.On Tuesday they threw their face masks into the air before boarding buses for flights home.A labeling error caused a person infected with coronavirus to be mistakenly released from UC San Diego Medical Center.The error was discovered as she was being returned to Marine Corps Air Station Miramar, where more than 200 Americans who evacuated China are under quarantine.She has since returned to the hospital.