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
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
Skin rashes and bleeding from the gums or nose may occur, and in severe cases, meningitis or encephalitis—inflammation of the brain and its membranes—may develop.
—Geraldine Castro, WIRED, 20 Dec. 2024
In severe cases, the infection can spread to the nervous system, causing meningitis or encephalitis.
—Yaakov Katz, Newsweek, 28 Nov. 2024
Already, the test has been effective at identifying the cause of neurological infections such as meningitis and encephalitis (swelling of the brain or its surrounding membranes), according to one of the new studies, published Tuesday in the journal Nature Medicine.
—Aria Bendix, NBC News, 12 Nov. 2024
See all Example Sentences for encephalitis 
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.
Eduardo Cuevas, USA TODAY, 5 Sep. 2024
Skin rashes and bleeding from the gums or nose may occur, and in severe cases, meningitis or encephalitis—inflammation of the brain and its membranes—may develop.
—Geraldine Castro, WIRED, 20 Dec. 2024
In severe cases, the infection can spread to the nervous system, causing meningitis or encephalitis.
—Yaakov Katz, Newsweek, 28 Nov. 2024
Already, the test has been effective at identifying the cause of neurological infections such as meningitis and encephalitis (swelling of the brain or its surrounding membranes), according to one of the new studies, published Tuesday in the journal Nature Medicine.
—Aria Bendix, NBC News, 12 Nov. 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 19 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.
Love words? Need even more definitions?
Merriam-Webster unabridged
Share