Zika RNA Found in Male Semen

Zika virus RNA has frequently been detected in the semen of men after Zika virus infection.

New research shows that male semen can host 27 different viruses, including the Zika virus.

This means the presence of the Zika virus in the male reproductive tract may increase the risk of sexually transmitted infections, and may reduce male fertility.

According to this research, finding the Zika virus RNA in the semen of men highlights our knowledge gaps regarding the persistence of viruses in genital fluids, especially semen.

The authors of this study published in Emerging Infectious Diseases conducted a wide search on PubMed and found evidence of 27 different viruses that can cause viremia documented in semen.

These researchers found that viruses such as Lassa fever, Rift Valley fever, and chikungunya, were also detected in semen.

"Given these findings, the following questions need to be addressed: which viruses are shed and remain viable in semen, for how long, and at what concentrations,” asked Dr. Alex Sala, a clinician and clinical researcher for the United Kingdom Public Health.

“The answers to these questions have implications for risks for sexual transmission and, therefore, embryonic infection, congenital disease, miscarriage, and effects on epidemiologic and transmission models," the authors conclude.

Infection of spermatozoa could result in transmission of virus-induced mutations to subsequent generations, thereby elevating risks for cancer and other disorders.

However, it is probable that many more viruses capable of causing viremia (presence of virus in the blood) can be found in semen.

Of those causing acute infections, only Zika and Ebola viruses have been systematically tested for in semen.

These researchers said ‘the presence of viruses in semen is probably more widespread than currently appreciated, and the absence of virus in genital secretions should not be assumed for traditionally non–sexually transmitted viruses.’

The investigation of virus detection and persistence in semen across a range of viruses is useful for clinical and public health reasons, in particular for viruses that lead to high mortality or morbidity rates or to epidemics.

No conflicts of interest were disclosed by either Dr. Salam is a clinician and clinical researcher for the United Kingdom Public Health Rapid Support Team; and Peter W. Horby, is Professor of Emerging Infectious Diseases and Global Health.