NEW YORK - 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 many have infected their female sex partners, who had not traveled.

Zika virus is mainly spread by mosquito bites. But there have been at least two reported cases of sexual transmission, including a recent case in Texas.

On Tuesday, the Centers for Disease Control and Prevention said the 14 cases include two pregnant women whose infections have been confirmed. Tests are pending for their male partners.

Zika virus causes - at worst - only mild symptom in most people. But in Brazil, health officials have reported an apparent link between Zika infection and a rare birth defect.