A pregnant woman in Los Angeles County who traveled abroad has tested positive for the Zika virus, county officials said in a news release Friday.
It is the second confirmed case of Zika virus in the county, according to the Los Angeles County Department of Public Health.
In both cases, the person was infected while traveling outside the country to an area of ongoing transmission, officials said.
Local transmission of the virus has not occurred in Los Angeles County, officials said.
The first case was reported in late January in a young girl from Los Angeles County who had traveled to El Salvador in November.
While the virus often causes no symptoms, experts are particularly concerned about pregnant women who are exposed to it because the virus appears to be linked to a recent surge in Brazil of cases of microcephaly, a birth defect in which babies are born with abnormally small heads.
Zika virus has been spread by mosquitoes in several countries throughout the Americas, and authorities have recommended that women who are pregnant consider postponing travel to those places where transmission of the virus is ongoing.
The Centers for Disease Control and Prevention has also warned travelers to such countries to take precautions to avoid mosquito bites.
While local transmission of Zika virus has not occurred, officials warned that the mosquito that can transmit it has been found in the San Gabriel Valley and in the eastern part of Los Angeles County.
"People can reduce the spread of Aedes mosquitoes by eliminating sites around their homes where mosquitoes may breed by getting rid of containers and any other sites where water may collect and mosquitoes lay their eggs," officials said in the news release.