Scientists are raising the possibility that the Zika virus can be transmitted by oral sex, perhaps even by kissing.
According to the New York Times, a letter to The New England Journal of Medicine today describes one such case in France.
The Times says a single incident may seem trivial, but until early this year, there was only one known instance of sexual transmission of the Zika virus — a 2008 case in which a mosquito researcher just back from Africa infected his wife in Colorado.
Now scientists believe that sexual transmission is an important driver of the Zika epidemic in the Americas.
Cases have been reported in 10 countries where no mosquitoes carry the virus, including France, Germany, Italy, Portugual and New Zealand.
In the French case, a 46-year-old man returned to Paris from Rio de Janeiro on February 10, shortly after experiencing Zika symptoms in Brazil.
According to the authors of the report, he and his 24-year-old partner were using oral sex as a form of birth control. However, the woman fell ill on February 20 and tested positive for Zika on February 23.
Doctors say oral sex was the most likely means of transmission.
But they say it is unlikely the virus can spread through casual kissing.