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
The most common symptoms are high fiver, cough, conjunctivitis and rash, with serious complications including ear infections, diarrhea, pneumonia and encephalitis.
—
Matt Leclercq, Fort Worth Star-Telegram, 8 Apr. 2025
Pneumonia and encephalitis, or infections of the lungs and brain respectively, are more common.
—Sarah Zhang, The Atlantic, 7 Apr. 2025
Before the measles vaccine was introduced in 1963, the United States saw hundreds of thousands of cases every year, many resulting in complications like pneumonia, encephalitis and death.
—Dr. Josh Green, CNN Money, 5 Apr. 2025
Complications can include pneumonia and encephalitis. Anyone who was exposed and starts to develop symptoms should immediately call their doctor, an urgent care center or emergency department.
—Katie Langford, Denver Post, 31 Mar. 2025
See All Example Sentences for encephalitis
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Matt Leclercq, Fort Worth Star-Telegram, 8 Apr. 2025
Pneumonia and encephalitis, or infections of the lungs and brain respectively, are more common.
—Sarah Zhang, The Atlantic, 7 Apr. 2025
Before the measles vaccine was introduced in 1963, the United States saw hundreds of thousands of cases every year, many resulting in complications like pneumonia, encephalitis and death.
—Dr. Josh Green, CNN Money, 5 Apr. 2025
Complications can include pneumonia and encephalitis. Anyone who was exposed and starts to develop symptoms should immediately call their doctor, an urgent care center or emergency department.
—Katie Langford, Denver Post, 31 Mar. 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 15 Apr. 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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