Feb. 26 (UPI) -- The U.S. Centers for Disease Control and Prevention announced Wednesday the first possible community transmission of the deadly coronavirus in the United States.
The CDC said a person from California has been diagnosed with COVID-19 despite not having come into contact with anyone infected with the virus or traveled to places where the disease is present.
"At this time, the patient's exposure is unknown," the CDC said in a release. "It's possible this could be an instance of community spread of COVID-19, which would be the first time this has happened in the United States."
The CDC defines community spread of an illness when the source of infection is unknown.
It said the California patient, who was detected through the U.S. public health system, may have come into contact with someone who recently traveled to one of several countries currently combating the spread of the disease.
The Solano County resident was receiving medical treatment in Sacramento County, according to the California Department of Public Health.
Dr. Sonia Angell, director of the CDPH, said they have been anticipating community transmission of the virus in the state given its close relationship with China where there have been more than 2,700 deaths from COVID-19 and 78,000 confirmed cases since the outbreak began in early December.
"That's why California has been working closely with federal and local partners, including healthcare providers and hospitals since the outbreak was first reported in China -- and we are already responding," Angell said in a statement.
The CDPH clarified that there have been two other instances of person-to-person transmission of the disease in Chicago, Ill., and in San Benito County, Calif., but both were infected after prolonged interaction with family members who had returned from Wuhan, China, the epicenter of the outbreak, and tested positive for the disease.
The United States now has a total of 15 confirmed cases of COVID-19, according to the CDC, in addition to three infected patients who came from the Wuhan and 42 passengers of the Diamond Princess cruise ship docked in Japan who were evacuated back to the United States earlier this month. California has seven confirmed cases of the disease.
"The federal government has been working closely with state, local, tribal and territorial partners, as well as public health partners, to respond to this public health threat," the CDC said in a statement. "Unprecedented, aggressive efforts have been taken to contain the spread and mitigate the impact of this virus."
The announcement follows U.S. President Donald Trump appointing Vice President Mike Pence to lead the nation's response to the virus. He will work with professionals, doctors and other officials on a response to the disease, Trump said.