The U.S. Centers for Disease Control and Prevention said on Tuesday it was investigating 14 new reports of possible sexual transmission of the mosquito-borne Zika virus, including several involving pregnant women.
In two of the suspected cases, the infection has been confirmed in women whose only known risk factor was sexual contact with an ill male partner who had recently travelled to an area where the virus is present, the agency said.
Testing of the male partners is still pending, the CDC said.
Mosquito bites remain the primary way the virus is spread, although sexual transmission is possible, the agency added.
The new cases, like the previously reported ones, involve possible transmission of the virus from men to their sex partners.
At this time, there is no evidence that women can transmit Zika virus to their sex partners, CDC said.
The agency again stressed the need to use condoms and other precautions.
The first known case of Zika virus transmission in the United States was reported in Texas in early February by local health officials, who said it likely was contracted through sex and not a mosquito bite.
There is no vaccine or treatment for Zika, which has caused outbreaks in at least 26 countries in the Americas.
CDC also issued a Health Advisory Notice on Tuesday, as the new reports suggest sexual transmission may be a more likely means of transmission for Zika than previously considered.
The agency in early February revised its guidelines for pregnant women to include a recommendation that even those without symptoms of the Zika virus should be tested after returning from affected areas.
(Reporting by Natalie Grover and Ankur Banerjee in Bengaluru; Editing by Sriraj Kalluvila)
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