: any of a family (Flaviviridae and especially genus Flavivirus) of single-stranded RNA viruses transmitted especially by ticks and mosquitoes and including the causative agents of dengue, hepatitis C, hog cholera, Saint Louis encephalitis, West Nile virus, and yellow fever

Examples of flavivirus in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The most common in the U.S. is West Nile Virus, a potentially fatal neurologic disease caused by a flavivirus carried by mosquitoes. Byerin Prater, Fortune Well, 1 July 2023 The Zika virus is a flavivirus closely related to notorious pathogens including dengue, yellow fever, Japanese encephalitis, and West Nile virus. Christie Wilcox, Discover Magazine, 1 Feb. 2016

Word History

Etymology

New Latin, from Latin flavus yellow + New Latin -i- + virus — more at virus

First Known Use

1974, in the meaning defined above

Time Traveler
The first known use of flavivirus was in 1974

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Cite this Entry

“Flavivirus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/flavivirus. Accessed 26 Mar. 2025.

Medical Definition

flavivirus

noun
1
capitalized : a genus of the family Flaviviridae of single-stranded RNA viruses that are transmitted by arthropod vectors and especially by ticks and mosquitoes and that include the causative agents of dengue, Japanese B encephalitis, Saint Louis encephalitis, West Nile fever, and yellow fever
2
: any virus of the genus Flavivirus or the family Flaviviridae

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