encephalitis
noun
en·ceph·a·li·tis
in-ˌse-fə-ˈlī-təs 
plural encephalitides
in-ˌse-fə-ˈli-tə-ˌdēz
: 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.
Examples of encephalitis in a Sentence
Recent Examples on the Web
Like West Nile, St. Louis encephalitis can be mild — or progress to a neuroinvasive disease.
—
Cara Lynn Shultz, Peoplemag, 3 Sep. 2024
Severe infections from West Nile virus are extremely rare, with less than 1% of cases leading to serious neurological diseases like encephalitis or meningitis.
—Stephanie Brown, Verywell Health, 1 Aug. 2024
Roughly 1 out of every 1,000 children who have measles infections will also have encephalitis.
—Kristen Jordan Shamus, Detroit Free Press, 13 July 2024
West Nile arrives In August 1999, several people in Queens came down with a mysterious illness, with symptoms that included encephalitis, or brain swelling, according to a U.S. Centers for Disease Control and Prevention report.
—Eduardo Cuevas, USA TODAY, 5 Sep. 2024
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Cara Lynn Shultz, Peoplemag, 3 Sep. 2024
Severe infections from West Nile virus are extremely rare, with less than 1% of cases leading to serious neurological diseases like encephalitis or meningitis.
—Stephanie Brown, Verywell Health, 1 Aug. 2024
Roughly 1 out of every 1,000 children who have measles infections will also have encephalitis.
—Kristen Jordan Shamus, Detroit Free Press, 13 July 2024
West Nile arrives In August 1999, several people in Queens came down with a mysterious illness, with symptoms that included encephalitis, or brain swelling, according to a U.S. Centers for Disease Control and Prevention report.
—Eduardo Cuevas, USA TODAY, 5 Sep. 2024
See all Example Sentences for encephalitis
Dictionary Entries Near encephalitis
Cite this Entry
“Encephalitis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/encephalitis. Accessed 29 Jan. 2025.
Copy CitationKids Definition
encephalitis
noun
en·ceph·a·li·tis
in-ˌsef-ə-ˈlīt-əs
(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
plural encephalitides
-ˈlit-ə-ˌdēz
: 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.
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