Health officials in Washington, Oregon and California on Friday reported new cases of coronavirus among people who have not traveled recently to countries hit hard by the outbreak or come into contact with anyone known to have the disease. The Washington State Department of Health announced late Friday that a high school student in Snohomish County, just north of Seattle, tested positive for the deadly virus and was in home isolation. The student had not recently traveled to areas where the disease had spread, indicating it may be a case of community transmission. Washington health officials also said a woman in her 50s in King County tested positive after traveling to Daegu, South Korea, the site of a major coronavirus outbreak. She, too, is in home isolation. Both cases in Washington were “presumptive positives,” officials said, meaning they were awaiting confirmation from the Centers for Disease Control and Prevention.

Earlier Friday, Oregon health officials reported a presumptive positive test in a resident in Washington County with no known travel history or contact with infected individuals. California also reported a second case of community transmission, in Santa Clara County, after reporting the nation’s first such case, in Solano County, earlier in the week. The four new cases Friday bring the total number of covid-19 cases detected through the U.S. public health system to 19, according to the CDC.