流行性乙型脑炎(乙脑)是乙型脑炎病毒引起的一种人畜共患的传染病。国内对家畜、家禽自然感染率的调查表明,在流行地区及流行季节猪为100％,其次为马、驴94％,牛92％,狗66％,再次为鸭、鹅、鸡等,其中猪为主要传染源。通常在人类流行前2—4周,本病已在猪中通过蚊——猪——蚊循环而广泛传播,随着蚊虫增多及其感染率增高,本病即在人群中流行。乙型脑炎主要通过蚊虫叮咬传播,因此在蚊虫活动活跃的夏季,乙型脑炎容易流行。人对乙脑病毒普遍是易感的,但感染后并不是所有的人都发病,大约在 Japanese encephalitis (JE) is a zoonotic infectious disease caused by Japanese encephalitis virus. A survey of natural infection rates of livestock and poultry in China shows that pigs are 100% in popular areas and popular seasons, followed by horses, donkeys 94%, cattle 92%, dogs 66%, and again ducks, geese and chickens, among which pigs As the main source of infection. Usually 2-4 weeks before the epidemic of human, the disease has been widely transmitted by the mosquito-porcine-mosquito cycle in pigs. As the mosquito increases and its infection rate increases, the disease prevails in the population. Japanese encephalitis is mainly transmitted by mosquito bites, so eruption of Japanese encephalitis is prevalent in mosquito-active summer. People are generally susceptible to Japanese encephalitis virus, but not all people are infected after infection, about