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
Serious complications include pneumonia and encephalitis.
—
Mandy Taheri, MSNBC Newsweek, 15 June 2025
Measles can cause a variety of complications including ear infections, pneumonia, encephalitis or death.
—Neha Mukherjee, CNN Money, 17 Apr. 2025
Patients can also suffer hearing loss from ear infections experienced during their illness, while those who develop acute encephalitis can suffer permanent neurological damage.
—Dylan Scott, Vox, 18 Mar. 2025
As well as hospitalization and death caused by complications — including pneumonia, encephalitis, diarrhea and dehydration — measles can cause long-term, debilitating health complications such as cognitive impairment and blindness.
—Sarah Ferguson, Forbes.com, 4 Apr. 2025
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.
Mandy Taheri, MSNBC Newsweek, 15 June 2025
Measles can cause a variety of complications including ear infections, pneumonia, encephalitis or death.
—Neha Mukherjee, CNN Money, 17 Apr. 2025
Patients can also suffer hearing loss from ear infections experienced during their illness, while those who develop acute encephalitis can suffer permanent neurological damage.
—Dylan Scott, Vox, 18 Mar. 2025
As well as hospitalization and death caused by complications — including pneumonia, encephalitis, diarrhea and dehydration — measles can cause long-term, debilitating health complications such as cognitive impairment and blindness.
—Sarah Ferguson, Forbes.com, 4 Apr. 2025
See All Example Sentences for encephalitis
Cite this Entry
“Encephalitis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/encephalitis. Accessed 3 Jul. 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