The epidemic season of B encephalitis is mainly summer and autumn. The full name of B encephalitis is epidemic B encephalitis, the previous name is called Japanese B encephalitis, its pathogen is B encephalitis virus. This pathogen is mainly distributed in the Asian region, the transmission route is mainly through the mosquito bite, so in the mosquito season, summer and autumn is the main season of epidemic B encephalitis. Patients infected by mosquito bites can directly infect the central nervous system and cause the onset of B encephalitis because of the strong neurophilic nature of the virus. Patients have an acute onset with high fever and impaired consciousness, often accompanied by convulsions, manifesting as tonic spasmodic seizures, which are symptomatic epilepsy, and positive meningeal stimulation signs on physical examination. If the treatment is not timely enough, the disease is severe and often leaves serious sequelae even after cure.