The epidemic season of BSE in Shanghai is from July to September every year, with the peak incidence from late July to early August. BSE is transmitted through the bite of mosquitoes carrying the BSE virus. Children and adolescents are the main causes of BSE. Clinical manifestations The main clinical symptoms of B encephalitis are high fever (temperature usually above 39℃ and persistently does not subside), severe headache, convulsions and meningeal irritation such as cervical tonicity, and clinical manifestations such as restlessness, impaired consciousness, drowsiness, coma, etc. Severe cases may die from respiratory failure or leave neurological sequelae.