Family Flaviviridae

Members of the family Flaviviridae have unsegmented, positive-strand RNA genomes that range in size from 9.5 to 12.5 kb. The genome serves as the sole mRNA and all viral proteins are cleaved from a large polyprotein precursor. Virions are enveloped with a diameter of about 30 nm. A single capsid protein (C) assembles to form the capsid. Two or three glycoproteins are associated with the envelope. There are four genera in the family Flaviviridae and three of these contain important human and animal pathogens. The genus Hepacivirus contains the human Hepatitis C virus, a blood-borne pathogen. Members of the genus Flavivirus are transmitted by insects (often mosquitos) and they have evolved to replicate in both animal and insect hosts. Human pathogens include dengue virus, yellow fever virus, and Zika virus. Several members of the genus Pestivirus are important pathogens of food animals.