L.A. County officials said Thursday that a woman had been infected with the Zika virus by her partner in the first case of sexually transmitted Zika virus in the county.
A man who lives in L.A. County traveled to Mexico and became infected with the Zika virus in early November, and shortly afterward his female partner, who didn't travel to Mexico, also developed the infection, officials said.
"This case is a reminder to take precautions during sex or avoid sex if you or your partner have traveled to an area with risk of Zika," said Dr. Jeffrey Gunzenhauser, L.A. County's interim health officer.
Zika virus, which has caused hundreds of babies to be born with birth defects in Brazil, is most commonly transmitted by mosquitoes. The virus can also be transmitted through sex, though that's much rarer.
Since 2015, there have been 122 cases of Zika infection in L.A. County, 121 of which were acquired while traveling to countries where the virus is spreading, such as Mexico and Brazil. There are no mosquitoes carrying the virus in L.A. County or elsewhere in California.
In California overall, there have been 619 cases of Zika virus since 2015, eight of which were sexually transmitted.
Health officials warned that people who travel to countries where Zika is a risk should wear mosquito repellent as well as long sleeves and pants. A couple in which one partner might have been exposed should follow national health guidelines for condom usage to prevent transmission to the other partner.
The virus can cause birth defects in pregnant women, so pregnant women should use condoms or abstain from sex for the length of their pregnancy if their male partner has been exposed to Zika virus, officials said.
Most people who are infected with Zika virus don't have symptoms. Those that do have symptoms might experience a fever, a rash or muscle pain that lasts for about a week.