[citation needed] Specific types include: Veterinarians have observed meningoencephalitis in animals infected with listeriosis, caused by the pathogenic bacteria L. monocytogenes.

L. monocytogenes meningoencephalitis has been documented to significantly increase the number of cytokines, such as IL-1β, IL-12, IL-15, leading to toxic effects on the brain.

[8][9] Meningoencephalitis is a rare, late-stage manifestation of tick-borne ricksettial diseases, such as RMSF and human monocytotropic ehrlichiosis (HME), caused by Ehrlichia chaffeensis (a species of rickettsiales bacteria).

The fungus, Cryptococcus neoformans, can be symptomatically manifested within the CNS as meningoencephalitis with hydrocephalus being a very characteristic finding due to the unique thick polysaccharide capsule of the organism.

[citation needed] Clinical diagnosis includes evaluation for the presence of recurrent or recent herpes infection, fever, headache, altered mental status, convulsions, disturbance of consciousness, and focal signs.