As fears over the Zika virus continue to mount in South America, new concerns are arising in the United States as health officials have documented the first known case of female-to-male transmission of the mosquito-borne virus. According to a report issued by the CDC and the New York City Department of Health and Mental Hygiene, a man in his 20s who had not traveled outside the U.S. over the last year, contracted the Zika virus after one instance of vaginal intercourse with a woman who had recently returned from a trip to a country where Zika has become an epidemic. The man did not wear a condom during the sexual intercourse, officials said in the report.
The report did not mention which country the woman, also in her 20s, visited. She is not pregnant, the report said, and had sex with the man upon returning from her journey. “She reported having headache and abdominal cramping while in the airport before returning to N.Y.C.,” the report noted. The following day, several telltale Zika symptoms emerged, including fever, fatigue, a rash, back pain, swelling of the extremities, and numbness in her hands and feet. It wasn’t until seven days after the two had had sex that the man began developing symptoms, which included pink-eye, a rash and joint pain.
According to Dr. Mary T. Bassett, New York City’s health commissioner, there are several factors that may have elevated the risk of infection in this case. For instance, Bassett said, the man is uncircumcised, the woman was in the early stages of her illness when the viral load was high, and her menstrual cycle, which she reported to doctors was heavier than usual, had just begun at the time of the sexual intercourse.
Until now, every previous case of Zika virus being transmitted from one person to another has involved a man infecting a woman. The reason for that is simple: Zika, scientists believe, thrives in semen. It actually has been shown to live longer in the male ejaculate than it does in blood, and beyond after a male patient’s Zika symptoms pass. But Zika’s lifespan in semen is still somewhat of a mystery and CDC officials are actually seeking Zika-infected semen — if you’ve got some, they want to pay you for it. A new study released just this week suggested the virus might also be communicable by women.