Common symptoms include fever, headache, vomiting, neck tonicity, convulsions, aphasia, hemiparesis, ataxia, involuntary movements, psychiatric disorders, impaired consciousness, and meningeal irritation signs. Patients with encephalitis show prominent brain parenchymal damage and are prone to convulsions, aphasia, hemiparesis, mental and intellectual impairment. Some lentiviral infectious encephalitis is dominated by mental abnormalities, manifesting as inattention, peculiar behavior, unresponsiveness, reduced speech, emotional indifference, and gradually muteness, a state of wooden rigidity, inability to care for oneself, and bed rest. Headache, vomiting, cervical tonicity and meningeal irritation signs are more prominent in patients with meningitis, and manifestations of focal brain damage are often seen in the later stages.