SAN FRANCISCO, Feb. 28 (Xinhua) -- The Santa Clara County Public Health Department in Northern California confirmed Friday a second COVID-19 case of unknown origin in the United States.
Santa Clara health officials said a female senior with chronic health conditions was found to be infected with COVID-19 when she was treated for a respiratory illness.
The county's Public Health Laboratory received the specimens Thursday and performed the testing. A final result of COVID-19 positive was confirmed Thursday night.
The female patient, whose identity detail was not disclosed for protection of her privacy according to law, had no known travel history nor exposure to any other infected people.
The health department said it has been working to identify the contacts and understand the extent of exposures relating to the new patient.
The woman was the third case of COVID-19 confirmed in Santa Clara, but she was different from the previous two cases where the two patients had a history of traveling to China or exposure to infected individuals.
"This new case indicates that there is evidence of community transmission but the extent is still not clear," said Sara Cody, director of the Santa Clara Public Health Department.
Health officials said the department will conduct community surveillance to determine the extent of local transmission.
On Wednesday, the U.S. Centers for Disease Control and Prevention confirmed the first case of person-to-person transmission of coronavirus in the country.
According to a daily report released by the World Health Organization till Friday, the total number of COVID-19 cases in the United States has risen to 59, including people evacuated from Wuhan, China, and the Diamond Princess cruise ship.
