Probable distribution of Zika virus based on virus isolation and seroprevalence.

*Earliest report, indicates either the first virus isolation or the first report of seroprevalence.†Seroprevalence was either determined by one or more of the following methods: Haemagglution inhibition, neutralization, complement-fixation, IgG and/or IgM ELISA. Of note, it is possible due to antigenic cross-reactivity among flaviviruses that seropostive individuals may have been previously exposed to one or more flaviviruses and not to Zika virus.‡Viral RNA sequenced from four patients (Lanciotti et al. 2008).