某初级中学2009-2014年甲型副伤寒疫情流行病学调查

了解宣恩县某初级中学2009-2014年间3次甲型副伤寒暴发疫情的原因,为从源头减少学校副伤寒疫情的发生提供依据.方法 采用病例对照研究方法,对病例的活动、饮水、饮食和接触史等开展流行病学调查,比较宣恩县副伤寒历史发病的流行病学特点和3次暴发疫情中病例临床治疗与转归情况,进行实验室证据询证调查.结果 该校2009,2013,2014年3次暴发疫情的罹患率分别为2.65%,2.76%,2.25%,无重症及死亡病例.监测集中式供水的75份水源水、末梢水及简易自流水、井水、桶装水,仅3份桶装水符合卫生标准,其余均显示细菌学超标,但均未检出沙门菌、志贺菌、大肠杆菌0157.68份校内外环境及病例家庭外环境标本、学生食堂1周的食品留样70份、校内外79名食品餐饮从业人员及21名病例家属的血培养、肛拭培养均未检出沙门菌及志贺菌.随机抽取健康教师18人、健康学生117人进行监测,学生中有3人血培养检出甲型副伤寒杆菌,10人血清肥达试验显示异常.2014年疫情发病的有7例系该校2013年暴发疫情时发生的病例,2009,2013年疫情中病例在住院期间抗生素平均治疗时间为8d,均没有达到规范治疗时间,且出院时均未按规范要求进行粪便培养.病例对照研究显示,与既往病例同班级、同桌、同宿舍、为好友等接触是危险因素(P值均<0.05).对2009-2014年分离出的38份甲型副伤寒菌株进行溯源分析,显示高度同源.结论 该校连续发生的暴发疫情主要是既往病人治疗不彻底,学校传染源发现不及时,致使传染源在校内积累,在适宜条件下引起疫情暴发.学校应加强传染病监测、发现、报告与管理机制,落实传染病的监测预警机制.

Trace-back investigation on consecutive Paratyphoid outbreak in a junior high school during 2009-2014

Objective To explore etiology of three consecutive Paratyphoid outbreak in a junior high school in Xuan'en County during 2009-2014,to reduce future outbreak risk and protect health of teachers and students.Methods Detailed history information on activities,drinking,diet and close contacts of the patients were collected.The outbreaks were compared with previous paratyphoid outbreak in Xuan'en County in epidemiological characteristics,clinical treatment and outcome.Laboratory tests were investigated,and traced back for possible risk factors.Results About 2.65%,2.76% and 2.25% of all students affected in the Paratyphoid outbreak,respectively,with no severe and fatal cases.Only 3 out of 75 water samples from centralized water supply,well and bottled water were eligible.No salmonella,shigella,eg.coli O157 was detected.No infectious agents was detected in 68 environmental specimens around school and patient house and 70 food samples from school canteen during the past week.Blood test and rectal swabs were negative among 79 canteen staffs and 21 family members.Eighteen healthy teachers and 117 students were randomly selected for health monitoring,3 students were detected salmonella paratyphi A and abnormal serum hypertrophy reaction was found in 10 blood samples.Seven patients in 2014 outbreak were the same students in 2013 outbreak.Average time for antibiotic treatment in hospital was 8 days,less than the standard treatment time,and no stool Salmonella culture before discharged from the hospital.Classmate,share the same table with patients,living in the same dormitory,close friend had the highest risk of being infected.PFGE source attribution analyses from in 38 Paratyphi strains in 2009-2014 showed high homologous rate.Conclusion Consecutive outbreak occurred in this school related with incomplete treatment on patients,no timely identification and proper management on source of infection.Schools,medical institutions play an important role in limiting the spread of infectious diseases by strengthen infectious disease monitoring and management guidelines.