encephalitis

noun

en·​ceph·​a·​li·​tis in-ˌse-fə-ˈlī-təs How to pronounce encephalitis (audio)
plural encephalitides in-ˌse-fə-ˈli-tə-ˌdēz How to pronounce encephalitis (audio)
: inflammation of the brain that is caused especially by infection with a virus (such as herpes simplex or West Nile virus) or less commonly by bacterial or fungal infection or autoimmune reaction

Note: Encephalitis may be asymptomatic or present with mild to severe symptoms (such as fever, headache, confusion, seizures, or loss of consciousness) sometimes progressing to coma or death.

encephalitic adjective

Examples of encephalitis in a Sentence

Recent Examples on the Web
These examples are automatically compiled from online sources to illustrate current usage. Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Brain problems: Rare complications include cerebellar ataxia (trouble with coordination), encephalitis (brain swelling), or meningitis (infection of membranes surrounding the brain and spine). Brandi Jones, Msn-Ed, Health, 18 Oct. 2024 Joe Casey, 54, is on a ventilator at Exeter Hospital, and has tested positive for eastern equine encephalitis (EEE), West Nile Virus, and St. Louis encephalitis — all mosquito-bourne illnesses. Cara Lynn Shultz, Peoplemag, 3 Sep. 2024 Two pools, comprising 46 mosquitoes from two ZIP codes, have also tested positive for the virus that causes St. Louis encephalitis. Chantelle Lee, TIME, 11 June 2024 About 1 in every 20 children will develop pneumonia, and others may develop a dangerous swelling in the brain called encephalitis. Deidre McPhillips and Jacqueline Howard, CNN, 2 Oct. 2024 See all Example Sentences for encephalitis 

Word History

First Known Use

1843, in the meaning defined above

Time Traveler
The first known use of encephalitis was in 1843

Dictionary Entries Near encephalitis

Cite this Entry

“Encephalitis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/encephalitis. Accessed 8 Nov. 2024.

Kids Definition

encephalitis

noun
en·​ceph·​a·​li·​tis in-ˌsef-ə-ˈlīt-əs How to pronounce encephalitis (audio)
(ˌ)en-
: inflammation of the brain
also : a disease marked by encephalitis

Medical Definition

encephalitis

noun
en·​ceph·​a·​li·​tis in-ˌsef-ə-ˈlīt-əs How to pronounce encephalitis (audio)
plural encephalitides -ˈlit-ə-ˌdēz How to pronounce encephalitis (audio)
: inflammation of the brain that is caused especially by infection with a virus (such as herpes simplex, varicella zoster, or West Nile virus) or less commonly by bacterial or fungal infection or autoimmune reaction

Note: Encephalitis may be asymptomatic or present with mild to severe symptoms (such as fever, headache, confusion, seizures, or loss of consciousness) sometimes progressing to coma or death.

encephalitic adjective

More from Merriam-Webster on encephalitis

Last Updated: - Updated example sentences
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