Napa County Public Health officials said a pregnant woman in the county tested positive for the Zika virus this week.
Doctors said she had traveled to Central America at some point but was not showing symptoms.
County Health Officer Dr. Karen Relucio says there is no threat to public health.
“The two kinds of mosquitoes that transmit the virus have not been found here,” she wrote.
More information about the Zika virus can be found on the Centers for Disease Control website.