Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology
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Diagnostic requests for both Zika virus (ZIKV) and dengue virus (DENV) infections in returning travelers have significantly increased during the recent ZIKV outbreak in the Americás. These flaviviruses have overlapping clinical syndromes and geographical distribution, but diagnostic differentiation is important because of different clinical consequences. As flaviviruses are known to have a short viremic period, diagnostics often rely on serological methods, which are challenging due to extensive cross-reactive antibodies. ⋯ Although the DENV NS1 antigen assay was highly specific in this cohort of laboratory confirmed ZIKV-infected travelers, we demonstrate high percentages of cross-reactivity of DENV IgM and IgG ELISÁs of which diagnostic laboratories should be aware. In addition, the high rate of DENV IgG background of >25% complicates a proper serological diagnosis in this group.