The University of Hong Kong

There are 34 people who have tested positive for coronavirus in the United States, according to an announcement Friday by the US Centers for Disease Control and Prevention.

This includes 21 cases among repatriated individuals, as well as 13 US cases.

"We are keeping track of cases resulting from repatriation efforts separately because we don't believe those numbers accurately represent the picture of what is happening in the community in the United States at this time," Dr. Nancy Messonnier, director of the CDC's National Center for Immunization and Respiratory Diseases, told reporters Friday.

About the cases: The 21 repatriated include 18 former passengers of the Diamond Princess cruise ship that docked in Japan, plus three who had been previously evacuated from China. There are 10 additional passengers among the Diamond Princess evacuees who tested positive for the virus in Japan, and who Messonnier said will likely be added to the official US count once the Japanese test results have been adjudicated.

The 13 US cases include seven in California, one in Massachusetts, one in Washington state, one in Arizona, two in Illinois and one in Wisconsin. Among these cases, there are two instances of person-to-person transmission, one in Illinois and one in California.

The 13th US case was confirmed overnight in Humboldt County, California. County officials offered few details but said a close contact with symptoms was also undergoing testing, and both are self-isolating at home.