伤寒是由伤寒杆菌引起的急性肠道传染病 ,它至今仍然是许多发展中国家发病率较高的传染病 ,据估计伤寒在全世界每年约有１６００万人次发病 ,死亡约６０万人［１］。因此伤寒仍是很多发展中国家重要的公共卫生问题之一。１伤寒菌苗研究史自１９世纪末德国的Ｐｆｅｉｆｆｅｒ和 Typhoid fever is an acute enteric disease caused by typhoid bacillus and is still a high-prevalence infectious disease in many developing countries. It is estimated that typhoid fever affects about 16 million people worldwide each year, resulting in about 600,000 deaths ]. Typhoid fever is therefore still one of the major public health problems in many developing countries. A history of typhoid bacterin researches in Germany since the late 19th century Pfeiffer and