Zika fever is caused by the Zika virus (ZIKV), an arthropod-borne virus (arbovirus). The Zika virus is a member of the Flavivirus genus in the family Flaviviridae. It is related to dengue, yellow fever, West Nile and Japanese encephalitis, viruses that are also members of the virus family Flaviviridae.
Video 1. What is Zika? WHO information video. Epidemiologist Erika Garcia provides more information about Zika virus disease.
Along with other viruses in the Flaviviridae family, Zika virus is enveloped and icosahedral with a non-segmented, single-stranded, positive sense RNA genome. It is most closely related to the Spondweni virus and is one of the two viruses in the Spondweni virus clade. Virus particles are 40 nm in diameter, with an outer envelope and a dense inner core. The Zika virus RNA is 10,617-nucleotide long. The Zika virus genome encodes for a polyprotein with three structural proteins, capsid, premembrane/membrane, and envelope (including the envelope-154 glycosylation motif previously associated with virulence), and seven nonstructural proteins, NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5 encodes for (see figure 1). Virions located on the surface of the cell membrane enter the host cells. The site of mRNA transcription is in the cell cytoplasm.
Figure 1. Zika virus genome structure