流行性乙型脑炎主要流行于远东各地,我国流行地区也甚广泛。西北地区在解放前,由于反动政府不重视人民健康,没有进行调查研究和防治工作,所以一直没有脑炎病例报告。自1951年8月上旬,西安市初次发现疑似病例,经血清学与病毒分离证实为流行性乙型脑炎以来,陕西省各地陆续有本病的报告。为了摸清西北地区流行性乙型脑炎地理上的分布,提供采用防治对策的科学根据,自1953年以 Prevalence of Japanese encephalitis is widespread in the Far East and is also widespread in endemic areas of our country. Before the liberation of Northwest China, there was no reported case of encephalitis since the reactionary government did not attach importance to people’s health and did not conduct investigations, studies and prevention work. Since early August 1951, the first detection of suspected cases in Xi’an City, serological and viral isolation confirmed since the epidemic of encephalitis, Shaanxi Province, one after another have the report of the disease. In order to find out the geographical distribution of Japanese encephalitis in Northwest China and provide a scientific basis for its prevention and treatment measures,