Specificity of Dengue NS1 Antigen in Differential Diagnosis of Dengue and Zika Virus Infection

To the Editor: Circulation of new arboviruses of the genus Flavivirus poses a major problem for differential diagnosis. Zika virus, a mosquitoborne virus of the family Flaviviridae, is closely related to other arboviruses circulating in the Americas, including dengue, yellow fever, Saint Louis encephalitis, and West Nile viruses (1,2). Serologic cross-reactivity between these arboviruses is common; thus, to ensure optimal patient care and accurate epidemiologic surveillance, an effective differential diagnosis is required in regions with active transmission of dengue virus and circulation of Zika virus (2–4).