The Centers for Disease Control and Prevention said Tuesday it is investigating 14 new reports of sexual transmission of Zika, including several involving pregnant women.
"In two of the new suspected sexual transmission events, Zika virus infection has been confirmed in women whose only known risk factor was sexual contact with an ill male partner who had recently traveled to an area with local Zika virus transmission," the CDC said in a statement. "Testing for the male partners is still pending."
Confirmatory tests are pending in four other suspected sexual transmission events, the CDC said. And an investigation is ongoing in eight other suspected events.
The new cases involve possible transmission of the virus from men to their sex partners, according to the CDC. Currently, there is no evidence that women can transmit Zika virus to their sex partners, but more research needs to be done.
Earlier this month, Dallas health officials reported the first known case of sexual transmission of Zika in the current outbreak. Zika has been spreading rapidly across the Americas, prompting the World Health Organization to declare it an international public health emergency.
Mosquito bites remain the primary vehicle for Zika transmission but sexual transmission of the virus infection is possible, the CDC said.