Acute encephalitis is an inflammation of the brain that can be caused by a variety of viruses, bacteria, and other pathogens. Common causes include enteroviruses, arboviruses like Japanese encephalitis virus, and herpes viruses. Clinical features depend on the area of brain involved but often include fever, headache, seizures, and altered mental status. Diagnosis involves examination of cerebrospinal fluid and blood tests. Management focuses on supportive care, monitoring for complications, and treating any underlying infection. Prevention strategies target reducing exposure to pathogens like mosquitoes that transmit certain viruses.