U. S. health officials are investigating more than a dozen possible Zika infections that may have been spread through sex.
The 14 cases all involve men who visited areas with Zika outbreaks, and who may have infected their female sex partners, who had not travelled to those areas.
Zika virus is mainly spread by mosquito bites, and sexual transmission has been considered rare. There have been two reported cases, including a recent one in Texas, and at least two other reports of the Zika virus found in semen.
Mosquito-borne Zika outbreaks have erupted across most of Latin America and the Caribbean in the last year. So far, all the 82 Zika infections diagnosed in the US have involved people who travelled to outbreak regions.