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

Anyone with questions about local mosquito populations or the West Nile virus can contact the Cincinnati Health Department at 513-352-2922. —Quinlan Bentley, The Enquirer, 12 July 2024

Advertisement The Greater Los Angeles County Vector Control District has found three cases of the West Nile virus in mosquito samples from the San Fernando Valley, and officials are on the lookout for more as this year’s heavy rainfall made conditions ripe for a mosquito takeover. —Jireh Deng, Los Angeles Times, 10 July 2024

The Louisville Metro Department of Public Health and Wellness will conduct mosquito fogging in three different Louisville zip codes in response to mosquitoes testing positive for West Nile virus, according to a release. —Ana Rocío Álvarez Bríñez, The Courier-Journal, 9 July 2024

The county announced in late June that one person, a blood donor, had tested positive for West Nile virus. —Elysee Barakett, NBC News, 5 July 2024

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