encephalitis

American  

[en-sef-uh-lahy-tis] / ɛnˌsɛf əˈlaɪ tɪs /

noun

Pathology.

1. inflammation of the substance of the brain.

2. Also called encephalitis lethargica. a form of this condition, caused by a filterable virus and characterized by apathy and abnormal sleepiness; sleeping sickness.

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encephalitis British  

/ ˌɛnsɛfəˈlaɪtɪs, ˌɛnkɛf- /

noun

1. inflammation of the brain

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encephalitis Scientific  

/ ĕn-sĕf′ə-lī′tĭs /

1. Inflammation of the brain, usually caused by infection with a virus.

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encephalitis Cultural  

1. An inflammation of the brain. Encephalitis may be caused by a virus or lead poisoning, or it may be a complication of another disease, such as influenza or measles. Encephalitis can cause permanent brain damage or death. It is also possible, however, to recover from it completely.

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Other Word Forms

• encephalitic
  adjective
• postencephalitic
  adjective
• pseudoencephalitic
  adjective

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Etymology

Origin of encephalitis

First recorded in 1835–45; encephal- + -itis

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Explanation

Encephalitis is a condition that causes the brain to swell and become irritated or inflamed. Most cases of encephalitis result from a virus. The term encephalitis comes from the Greek enkephalos, "brain," and the medical suffix -itis, used for diseases characterized by inflammation. Certain kinds of infections or disorders of the immune system can result in this inflammation of the brain. Encephalitis is quite rare, and though it's often so mild that it causes no symptoms, it can be serious.

Example Sentences

See Examples For:

encephalitis

There is, as Tbakhi experienced, a potential for continued complications—as well as long-term neuralgic pain called postherpetic neuralgia, blindness, and encephalitis.

From Slate ● Nov. 1, 2026

A severe measles case can cause pneumonia; encephalitis, or dangerous inflammation of the brain; hospitalization; and sometimes death.

From Los Angeles Times ● Aug. 6, 2026

His polio research was interrupted by World War II, during which he worked on a vaccine for Japanese encephalitis.

From The Wall Street Journal ● Jun. 21, 2026

The findings, published in Nature Communications, explain how viruses responsible for illnesses such as polio, encephalitis, myocarditis, and even the common cold take control of cellular machinery to copy themselves.

From Science Daily ● May 13, 2026

I slip off my flats and walk down the front porch steps, while Mother calls out for me to put my shoes back on, threatening ringworm, mosquito encephalitis.

From "The Help" by Kathryn Stockett

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