A fourth case of novel coronavirus was reported in Santa Clara County, California, according to the county's Public Health Department.

The case involves an adult woman who was in contact with another coronavirus patient in the county, the department said in statement on Saturday. She is not ill or hospitalized and is isolated at home, the statement said.

More on this: This means there are 70 confirmed and presumptive positive cases of novel coronavirus in the United States. A presumptive positive case has tested positive by a public health lab and is pending confirmation from the US Centers for Disease Control and Prevention.

These include 44 people who were aboard the Diamond Princess cruise ship and three people repatriated from China, according to the CDC.

With the new Santa Clara County case, there are 23 US cases in Arizona, California, Illinois, Massachusetts, Oregon, Washington state and Wisconsin. Thirteen of these cases are travel-related and 10 are linked to person-to-person spread. Cases are cumulative from January 21.