New York City reported the first ever female-to-male sexual transmission of the Zika virus on Friday. All previously reported sexual transmissions were spread from men to their sex partners, according to the CDC.
In this female-to-male case, a woman in her twenties traveled to an area with active Zika transmission and had condomless vaginal sex with a man on the day she returned to the United States. She developed Zika symptoms a few days later and was tested by her physician, who confirmed the infection.
The male partner, also in his twenties, developed Zika symptoms seven days after sexual intercourse and his infection was confirmed by a physician. He had not traveled outside the U.S. prior to infection.
"The timing and sequence of events support female-to-male Zika virus transmission through condomless vaginal intercourse," according to the CDC. "Ongoing surveillance is needed to determine the risk for transmission of Zika virus infection from a female to her sexual partners."
The CDC now recommends that all pregnant women who have a sex partner who traveled to an area with active Zika transmission to use barrier methods or abstain from sex during the pregnancy.