Persistence and infectivity of Zika virus in semen after returning from endemic areas: Report of 5 cases

- Detection of ZIKV RNA in semen by molecular testing can be used for diagnosis of Zika virus infection of cases returning from endemic areas and men can act as ZiKV reservoir during months.
- ZIKV is excreted by both symptomatic and asymptomatic patients (68 days) and longer than in symptomatic ones.
- Cell culture performed from semen samples demonstrated that the detected virus was infectious.
- Phylogenetical analysis strongly suggested male to female sexual transmission in one case in this study.

BackgroundThere are limited data about the persistence and infectivity of Zika virus in semen of symptomatic travelers returning from endemic areas and even less data in asymptomatic cases.ObjectiveWe investigated the persistence and infectivity of ZIKA virus in semen in five patients with Zika virus infection returning to Spain from endemic areas.Study designWe evaluated the epidemiological, clinical and virological characteristic of the five patients. In semen we detected ZIKA virus by PCR, partial sequencing and cell culture. We also performed phylogenetic analysis.ResultsWe detected Zika virus RNA (Asian lineage) by PCR in semen samples from day 14th to day 96th since the day of illness onset. Semen viral culture was positive for Zika virus in two patients at days of illness 30 and 69 by virus propagation. Phylogenetic analysis strongly suggested male to female sexual transmission in a couple returning from Maldives.ConclusionThis case series confirms that Zika virus RNA can be detected in semen up to three months after infection. Viral culture of semen samples shows prolonged infectivity that can lead to sexual transmission of Zika virus.