Sexual Transmission of Zika Virus and Persistence in Semen, New Zealand, 2016.

To the Editor: Zika virus infection is an emerging arboviral disease linked to an increased risk for severe neurologic outcomes and devastating adverse fetal complications, including pregnancy loss and congenital microcephaly (1). Most Zika virus infections result from bites from mosquito vectors; however, increasing evidence indicates that Zika virus infection can be sexually transmitted (1–3). Probable sexual transmission from male to female (3–5) and male to male (6) have been reported, and transmission through vaginal, anal (6), and oral (5) sexual intercourse has been implicated. Studies also have demonstrated the presence of Zika virus RNA in semen 2 weeks after symptom onset, with viral loads ≈100,000 times greater than those detected concurrently in serum (7), and Zika virus RNA has been detected in semen while being undetectable in serum (2,5,8). The presence of Zika virus RNA in semen up to 62 days after symptom onset of Zika virus infection has been reported (8). Here we report a case of locally acquired Zika virus infection that was almost certainly the result of sexual transmission and our findings indicating the duration of Zika virus RNA persistence in semen.