The Zika virus (ZIKV), which has now spread to at least 48 countries including the United States, is associated with adverse birth outcomes. While commonly transmitted by Aedes mosquitoes, ZIKV transmission may also occur via other modes including via transfusion and sexual routes. Since sexual transmission may pose a greater risk to growing fetuses, researchers at the U.S. Centers for Disease Control and Prevention conducted a prospective study and collected semen and urine samples from ZIKV infected men twice a month until viral RNA was not detectable by real-time reverse-transcriptase-PCR. Based on individual data from 184 men, only 4% of the participants (n=7) had detectable ZIKA RNA in their urine, but ZIKA RNA shedding in semen was much more common and was found in 33% of the men (n=60) over the study period. Viral shedding was found to decrease after the first 90 days of illness; detectable viral RNA was found in 61% of men during the first 30 days from illness onset but only 7% of men after at least 90 days of illness. One man, however, continued to shed a low level of virus for over 6 months. Further research is needed in order to determine the risk of transmission and define effective prevention strategies.
References:
- Mead PS, Duggal NK, Hook SA, et at. Zika Virus Shedding in Semen of Symptomatic Infected Men. The New England Journal of Medicine 2018; 378 (15); 1377-1385.
- Feldmann H. Virus in Semen and the Risk of Sexual Transmission. The New England Journal of Medicine 2018; 378 (15); 1440-1441.
