IFNAR1 and infection: In the presence of anti-Ifnar1 antibody, high levels of viral RNA (105 to 108 focus-forming unit (FFU) equivalents/g or ml) and infectious virus (up to 108 plaque forming units (PFU)/g or ml) were detected in the testis, epididymis, and the fluid collected from the epididymis within seven days of infection with either of the two ZIKV strains but not DENV (Fig 1a–c).