Basic information and current topics regarding Flaviviridae

Methods of Transmission

As you may have noticed from the taxonomy page, flaviviruses are often classified regarding their transmission vector (ex: tick-borne encephalitis virus group). It is, after all, a rather valid attribute of classification—since grouping by genome sequence often concurs with grouping by vector1.

There are four categories of ecological and genomic division for flavivirus. Two of these groups use the mosquito as their transmission vector. As stated in the vaccine section, almost half of all flaviviruses use the mosquito vector for transmission. Another group is founded by the flaviviruses using ticks as their vectors, and a final group represents the flaviviruses without a (known) vector1.

Notice how flaviviruses use only invertebrates as their transmission vectors and how flaviviruses infect primarily vertebrates. Flaviviruses are grouped separate from other Flaviviridae because of this peculiarity—that is, the ability to infect both vertebrates and invertebrates as well as their strange methods of transmission.

Below is a link to an animation which explains how mosquitoes transmit Dengue Virus:

World Health Organization – Dengue Virus Video

West Nile Virus

Picture Source: http://www.cdc.gov/niosh/topics/westnile/qanda.html

Japanese Encephalitis Virus (JEV)

JEV Picture Source: http://www.medindia.net/patients/patientinfo/encephalitis.htm

St. Louis Encephalitis Transmission Cycle

Source: http://www.cdc.gov/sle/technical/transmission.html


1. Chambers, T. J., & Monath, T. P. (January 1, 2003). The Flaviviruses: Structure, replication, and evolution. p. 214-240.

2. Sayers EW, Barrett T, Benson DA, Bryant SH, Canese K, Chetvernin V, Church DM, DiCuccio M, Edgar R, Federhen S, Feolo M, Geer LY, Helmberg W, Kapustin Y, Landsman D, Lipman DJ, Madden TL, Maglott DR, Miller V, Mizrachi I, Ostell J, Pruitt KD, Schuler GD, Sequeira E, Sherry ST, Shumway M, Sirotkin K, Souvorov A, Starchenko G, Tatusova TA, Wagner L, Yaschenko E, Ye J (2009). Database resources of the National Center for Biotechnology Information. Nucleic Acids Res. 2009 Jan;37(Database issue):D5-15. Epub 2008 Oct 21.

3. Benson DA, Karsch-Mizrachi I, Lipman DJ, Ostell J, Sayers EW (2009). GenBank. Nucleic Acids Res. 2009 Jan;37(Database issue):D26-31. Epub 2008 Oct 21.