In Santa Clara County, a woman and the family she is staying with are being quarantined and she is now in isolation at their home, Santa Clara County health officials told a news conference. The woman was not sick enough to require hospitalization, it added.

Axar.az reports citing foreign media that the other two cases involve a married couple in San Benito County, the San Benito County Public Health Services announced in a release late Sunday.

The U.S. Centers for Disease Control and Prevention (CDC) informed county health officials of the case Sunday morning, said Sara Cody, health officer of the Public Health Department of the County of Santa Clara.

U.S. health officials have said risks to the United States remain low.