St. Louis encephalitis /sānt lo̅o̅″is/ [St. Louis, Missouri; Gk, enkephalon, brain, itis, inflammation] , a flavovirus infection of the brain transmitted from birds to humans by the bite of an infected mosquito. It occurs most commonly in the central and southern parts of the United States and is characterized by headache, malaise, fever, stiff neck, delirium, and convulsions. Sequelae may include visual and speech disturbances, difficulty in walking, and personality changes. Convalescence may be prolonged, and death may result. No antivirus agent or vaccine is available. Treatment is supportive. Compare California encephalitis, equine encephalitis. See also encephalitis.
