Flavivirus transmission focusing on Zika

- Zika virus is a member of the genus Flavivirus, family Flaviviridae.
- Transmitted in two ecologically and phylogenetically distinct transmission cycles.
- Vectored mainly by Aedes spp. mosquitoes in either transmission cycle.
- Its host range recently expanded to include the Western Hemisphere.

Flaviviruses are among the most diverse viruses with over 85 species recognized. Taxonomically, this genus is one of the 4 recognized genera within the family Flaviviridae. Most flaviviruses of human public health significance, for example, dengue, yellow fever and Zika viruses, are arthropod-borne (arboviruses) and have two evolutionarily and ecologically distinct transmission cycles: a sylvatic transmission cycle, where the virus circulates between zoonotic vertebrate reservoir and amplification hosts and arboreal mosquitoes; and an urban transmission cycle, where the virus circulates between humans and peridomestic Aedes spp. mosquitoes. Zika virus (ZIKV), a flavivirus closely related to West Nile, dengue, Spondweni, Japanese encephalitis and yellow fever viruses, remained in obscurity since its discovery in 1947, but has recently emerged to cause a series of epidemics in the South Pacific, and most recently reaching nearly pandemic levels with its introduction in the Americas. Available epidemiologic and experimental evidence points to Aedes aegypti as the principal urban vector, possibly supplemented by Aedes albopictus in some locations. Unfortunately, the former is one of the most difficult mosquitoes to control owing to its highly anthropophilic behavior.