What does encephalitides mean?
Encephalitides is the formal plural of encephalitis, denoting multiple cases, types, or instances of inflammation of the brain. Such inflammation may arise from viral infections — including mosquito-borne illnesses like Japanese encephalitis and West Nile virus — from autoimmune reactions, or as a complication of other diseases. The word belongs firmly to medical register: it appears in neurology journals, epidemiological surveillance reports, and clinical textbooks, but rarely in general conversation, where speakers tend to say 'cases of encephalitis' instead. Its form reflects classical scholarship, borrowing the Greek-derived plural ending -ides used for nouns ending in -itis. For readers of medical literature, recognizing it is useful because authors often use the plural precisely to emphasize that brain inflammation is not one disease but a family of distinct conditions with different causes, courses, and treatments.
noun (plural)The plural of encephalitis: inflammations of the brain, typically caused by viral infection, autoimmune reaction, or other disease processes.
- Multiple instances or types of inflammation of the brain; the plural of encephalitis.
"Physicians tracked several distinct encephalitides that emerged in the region during the summer months."
"Japanese and West Nile viruses are among the best-known causes of arboviral encephalitides."
"Neurologists distinguish between infectious encephalitides and autoimmune forms when planning treatment."
This form is itself a plural; the anglicized alternative 'encephalitises' exists but is far less common. Use singular 'encephalitis' for a single condition.
"Several encephalitides were reported after the outbreak."
In medicine, even 'brain inflammation' refuses to stay singular — doctors who deal with more than one case must switch to the Greek-style plural encephalitides.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of encephalitides
Encephalitides derives from the Greek roots enkephalos ('brain', literally 'within the head') combined with -itis, the suffix denoting inflammation. The singular encephalitis entered English medical vocabulary in the nineteenth century, following the pattern of other -itis terms for inflammatory diseases coined in that era. Its plural follows the classical Greek declension, replacing the final syllable with -ides, a learned alternative to the anglicized encephalitises. Cognate formations sharing the same root include encephalopathy, encephalogram, and the adjective encephalitic.
Related word forms
How encephalitides is actually used
Strictly a technical term confined to medical and scientific writing. It appears almost exclusively in clinical literature and epidemiological reports rather than everyday speech, where writers usually rephrase to avoid the awkward plural.
Easily confused with encephalitides
Encephalitis is the singular form referring to one instance of brain inflammation, while encephalitides is its formal plural referring to multiple such conditions or cases.