West Nile virus

noun

variants or less commonly West Nile

1

: a flavivirus (species West Nile virus of the genus Flavivirus) that causes an illness marked by fever, headache, muscle ache, skin rash, and sometimes encephalitis or meningitis and that is spread especially from birds to humans by mosquitoes

2

or West Nile fever : the illness caused by West Nile virus

Examples of West Nile virus in a Sentence

Recent Examples on the Web

But these flying pests can also carry the West Nile virus, a disease that can cause fever, rash and muscle aches. —Caralin Nunes, The Arizona Republic, 16 Mar. 2024

Goodman said that the mosquitoes recently spotted in the Sacramento area are not the same species pose a threat for West Nile virus, a common disease spread by mosquito bites. —Hanh Truong, Sacramento Bee, 27 Feb. 2024

Fortunately, these aggressive mosquitoes are not the same species that carry the West Nile virus, which can be deadly to humans who are infected with the disease. —Rosalio Ahumada, Sacramento Bee, 9 Feb. 2024

In rare cases, West Nile virus can make people extremely ill and even kill them. —City News Service, San Diego Union-Tribune, 21 Sep. 2023

Future warming is projected to lead to the expansion of West Nile virus in the Northeast over the next 50 years. —Olivia Ferrari, Smithsonian Magazine, 5 Feb. 2024

Some of the most severe diseases mosquitoes carry and spread among humans are malaria, West Nile virus, Eastern equine encephalitis, yellow fever, dengue and Zika, according to the Centers for Disease Control and Prevention. —Julia Jacobo, ABC News, 6 Dec. 2023

Advertisement The disease is spread by the bites of infected Culex mosquitoes and is in the same virus family as West Nile virus, with similar transmission and symptoms, according to the health department. —Summer Lin, Los Angeles Times, 10 Nov. 2023

In August, one of Brady’s neighbors contracted West Nile virus from a mosquito bite and was paralyzed by the disease. —Hailey Branson-Potts, Los Angeles Times, 6 Oct. 2023

Word History

Etymology

from West Nile province of Uganda, where the virus was isolated in 1937

First Known Use

1940, in the meaning defined at sense 1

Medical Definition

West Nile virus

noun

variants also West Nile

1

: a single-stranded RNA virus of the genus Flavivirus (species West Nile virus) that causes an illness marked by fever, headache, muscle ache, skin rash, and sometimes encephalitis or meningitis, and that is spread especially from birds to humans by mosquitoes chiefly of the genus Culex

Note: West Nile virus is closely related to the viruses causing Japanese B encephalitis and Saint Louis encephalitis.

West Nile virus causes unusually severe infections in crows and blue jays, according to one CDC-led study that measured the number of virus particles in the birds' blood …

—Stephen S. Hall, Smithsonian

Of 5780 cases of arboviral disease reported in 2012, West Nile virus infection accounted of 5674, or 98% of the total, researchers reported in the Morbidity and Mortality Weekly Report.

—Rebecca Voelker, The Journal of the American Medical Association

2

or West Nile fever : the illness caused by West Nile virus

West Nile virus is such a disease. Last week, President Clinton declared an emergency in areas of New Jersey affected by the virus …

—James Ridgeway, The Village Voice

… residents are being urged to stay indoors while trucks spray insecticides through the streets to ward off outbreaks of West Nile fever, a mosquito-spread disease that last summer sickened dozens and killed seven.

—Joannie Schrof Fischer et al., U.S. News & World Report

see west nile encephalitis