CDC researchers have engineered West Nile/dengue virus (WN/DENV) chimeras utilizing the replicative ability of the West Nile (WN) virus but presenting the immunogenic pre-membrane and envelope surface proteins of each of the four dengue virus serotypes (DENV 1-4). When coupled with a fluorescent reporter gene, each chimera is able to generate live chimeric reporter WN/DENV (R-WN/DENV) expressing the fluorescent protein in infected cells. These chimeric reporter viruses (CRVs) are used to develop faster and less hands-on high throughput neutralization assays for DENV. In addition, the same CRV platform was also used to develop a chimeric reporter-West Nile/Zika virus (R-WN/ZIKV) (see related technologies below) for the ZIKV neutralization assay. Using a robust WNV replicative vector combined with a reporter that emits a very strong signal, this platform permits live-image detection and measurement of infectivity in 24-30 hours after cell infection by these reporter viruses. A high throughput neutralization assay without labor intensive procedures (such as cell overlay, cell fixation, and/or immunostaining) has been successfully developed for all these 5 CRVs using a live-image based plate reader. With similar replication kinetics for these CRVs, the test protocols can be synchronized for all of these 5 viruses, which is advantageous for samples that may need to be tested against more than one of these viruses for confirmative serologic diagnosis.