First case of female-to-male Zika transfer found in US

US health authorities said on Friday that a couple in New York has been diagnosed with the virus after they had sex following the woman's trip to a country where Zika is endemic. Prior to this case, all known cases of sexual transmission of Zika were male-to-female.

The woman had unprotected sex with her partner after returning from her trip and then shortly thereafter developed Zika-like symptoms. She was diagnosed with the virus after seeing a doctor, and a week after they had sex her partner reported the same symptoms. He too then was diagnosed with Zika.

Both have since recovered, according to the CDC. Officials withheld most other information about the couple, including their names and the dates of the woman's trip, disclosing only that they were in their mid-twenties.

Sexual transmission still uncommon

Though some health experts said they weren't surprised by the finding, the case negates previously held assumptions that the virus could only be transmitted sexually from men to "receptive partners."

The CDC said it was also altering its advice to take into consideration lesbian couples, though there have been no reported cases of woman-to-woman transfer of Zika.

Sexual transmission of the virus is still relatively rare; Zika is mainly spread through the Aedes aegypti mosquito. However, there have been documented cases of sexual transmission of Zika in 11 countries.

Zika shadow looms over Brazil

Fear over Zika has been steadily mounting as the world prepares for the Summer Olympic Games in Rio in August. On Friday, Wimbledon finalist Milos Raonic announced he wouldn't participate in the games due to concern about the virus.

A number of athletes have declined to participate thanks to Zika include Americans Jordan Spieth, John Isner and Sam Querrey and Australians Bernard Tomic and Nick Kyrgios.

The virus isn't known to cause serious health risks to adults; instead, it's seen mainly as a threat to pregnancies.

blc/bw (dpa, AFP, AP)