一、疫情概况:近年来在卫生设施及水源改善较好的国家,伤寒、付伤寒的发病率逐年下降。世界各国的伤寒病死率从10%降到1%以下。有的国家1/3病例来自海外输入者占伤寒病例中54%,而在乙型付伤寒中占21%,英国1977年发生伤寒261例,89%系从国外感染,11%在国内感染。各个国家的Vi噬菌体型的分布不尽相同,同一国家不同地区噬菌体分布也不完全相同,所以噬菌体分型在判断是当地菌株或 First, the outbreak situation: In recent years, better health facilities and water sources in the country, the incidence of typhoid fever, typhoid decreased year by year. Typhoid mortality in all countries in the world dropped from 10% to less than 1%. In some countries, one third of cases were imported from overseas, accounting for 54% of cases of typhoid, 21% of cases of typhoid B, and 261 cases of typhoid fever in 1977 in the United Kingdom, with 89% being infected from abroad and 11% being infected in the country. The distribution of Vi phage in different countries is not the same, and the distribution of phage in different regions of the same country is not exactly the same. Therefore,