Abstract
BACKGROUND: Zika virus (ZIKV), a mosquito-borne flavivirus, remains a concern for reproductive health despite the waning of the 2015-2016 epidemic. Unique among arboviruses, ZIKV can be sexually transmitted, with viral RNA persisting in semen beyond the acute phase, posing potential risks to male fertility and assisted reproduction. This narrative review provides clinicians with a contemporary understanding of ZIKV epidemiology, virology, and its implications for male reproductive care. RESULTS: ZIKV transmission has stabilised into low-level endemicity in Central and South America, with Europe reporting sporadic travel-associated cases. Persistence in semen is underpinned by infection of immune-privileged testicular tissues, including Sertoli, Leydig, and germ cells, enabling RNA detection for months post-infection even after systemic symptoms resolve. While replication-competent virus is rarely isolated beyond 4-6 weeks, viral RNA has been detected in semen over 180 days in rare cases. Clinically, ZIKV infection is associated with transient declines in sperm count, motility, and increased DNA fragmentation, likely mediated by inflammation, blood-testis barrier disruption, and impaired testosterone biosynthesis. Human studies suggest recovery of semen quality in most cases, but animal models demonstrate more persistent testicular damage and subfertility, supporting potential long-term reproductive impact. Current WHO guidance recommends a 3-month deferral from conception for men with confirmed or suspected ZIKV exposure. In assisted reproduction, cryopreserved semen from recently exposed individuals may retain viral RNA, requiring stringent handling and closed-system storage. Routine semen PCR testing is not widely adopted due to sensitivity limitations and inability to distinguish infectivity; thus, risk stratification based on travel and exposure history remains central to decision-making. In clinical practice, this risk stratification typically applies to men undergoing fertility assessment with recent travel to ZIKV-endemic regions, particularly in Central or South America, with compatible symptom history or recent onset infertility. CONCLUSIONS: ZIKV remains a relevant consideration in andrology and fertility practice, particularly in regions with ongoing endemic transmission and in individuals with travel-related exposure. Awareness of its virological properties, reproductive implications, and guidance for pre-conception counselling, laboratory practice, and semen storage is crucial. With appropriate precautions and patient education, most couples can safely proceed with fertility planning following ZIKV exposure.