A second case of COVID-19 with an unknown origin was identified in Santa Clara county, California on Friday, and two other potential cases of unknown origin were identified in Oregon and Washington state. This indicates to health experts that the novel coronavirus — which causes the disease COVID-19 — is likely spreading through more than one community in the US.

The Washington Post first reported news of the second case of community transmission in the US — a 65-year-old woman who had no known history of travel to any of the countries that have been hardest-hit by the disease. She has chronic health conditions and was originally hospitalized for a respiratory illness, said Sara Cody, the Santa Clara County Health Officer. Her doctor contacted health officials on Feb. 26 to test her for the novel coronavirus.

“This new case indicates that there is evidence of community transmission, but the extent is still not clear,” Cody said in a press conference. Officials said that eight California counties are now able to test for coronavirus. Up to 1,200 people can be tested with the CDC kits, the California Department of Public Health announced today.

So far, more than 84,000 cases of COVID-19 have been confirmed around the world, and more than 2,800 people have died of the respiratory disease. Most of these cases are concentrated in China, where the virus was first identified, but the disease has since spread around the world, with South Korea, Italy, Japan, and Iran among the hardest-hit.

Despite the global spread, the US has lagged in testing people who showed symptoms of the disease. Until this week, the Centers for Disease Control and Prevention had only tested people who had traveled to one of the most affected areas or had been in close contact with someone who had been diagnosed with the disease. In the case of the first patient who had COVID-19 of unknown origin, the hospital where she was being treated immediately requested a CDC test on February 19th, when the patient arrived. The CDC didn’t get around to testing the patient until February 23rd. The positive test results were announced on February 26th.

The CDC’s restrictive criteria coupled with a complicated test and convoluted rollout led to an intense public backlash. The agency expanded their testing requirements on Friday to include people who had traveled to a wider swath of geographic areas during the past 14 days. It also began allowing testing for people who had both severe symptoms and no diagnosis of other diseases like the flu.

The case announced in California today appears to be part of that last group. The woman apparently had no connection to any patients who were confirmed to have the disease, and had also not traveled to any area where the virus is known to be circulating. That means she may have gotten it from someone in the US who has not been diagnosed. Both cases were diagnosed in the San Francisco Bay Area, a geographical region that includes nine counties. The first case, in Solano County, was in the north part of the region; the second case, in Santa Clara, is about 90 miles away.

“I think there’s a strong possibility that there’s local transmission going in California,” said Jennifer Nuzzo, senior scholar at the Johns Hopkins Center for Health Security, in an interview with The Washington Post. “In other words, the virus is spreading within California, and I think there’s a possibility other states are in the same boat. They just haven’t recognized that yet.”

Soon after the second California case was announced, health officials in Washington state and Oregon also each announced the identification of cases of unknown origin in their state. In Oregon, an elementary school worker who hadn’t had contact with any confirmed case — and who hadn’t traveled to areas known to have the virus — was tested for the disease. Officials said in a statement that while they were still waiting for official results from the CDC they considered this a presumptive case. The elementary school where they worked will be closed until Wednesday for cleaning, the Associated Press reported.

Hours later in Washington, officials announced that they had also identified two presumptive new cases of COVID-19. One case involved a woman who had recently traveled to an area in South Korea where the virus was spreading. The other involved a high school student who became ill on February 24. The student did not attend classes while he had symptoms, but the school announced that it will be closed on Monday for cleaning. The student had not had any contact with people known to have the virus, and the source of their infection remains unknown.

Update 2/28/20 7:47PM ET: Adds details about the Santa Clara patient and test kits.

Update 2/29/20 9:08AM ET: Adds details about the cases in Oregon and Washington.