Health officials have confirmed that someone in Dallas County, Texas, contracted the Zika virus through sexual contact.
It's the first U.S. case related to the recent Western Hemisphere outbreak to be acquired through sex. Until now, experts have focused on transmission of the virus through mosquito bites.
Dallas County Health and Human Services says the patient, who remains anonymous, became infected after having sexual contact with someone who was ill and had returned from a country where the Zika virus is present.
The Centers for Disease Control and Prevention released this statement:
"CDC has confirmed through laboratory testing the first U.S. case of Zika virus infection in a non-traveler in the continental United States. According to a Dallas County Health Department investigation, a person who recently traveled to an area with Zika virus transmission returned to the United States and developed Zika-like symptoms. The person later tested positive for Zika, along with their sexual partner, who had not traveled to the area. In this instance there was no risk to a developing fetus.
"Based on what we know now, the best way to avoid Zika virus infection is to prevent mosquito bites. We do not have definitive information on the infectious time period, and will provide more guidance for individuals and clinicians as we learn more. Sexual partners can protect themselves by using condoms to prevent spreading sexually transmitted infections. People who have Zika virus infection can protect others by preventing additional mosquito bites."
In 2008, a Colorado researcher reportedly caught the virus overseas and may have spread it to his wife when he returned to the U.S.