学校聚集性结核病疫情处置中对接触者进行胸片随访的意义

The significance of chest X-ray follow-ups for contacts in disposition of the outbreak of clustered tuberculosis in a school setting

目的 分析一起学校聚集性结核病疫情,探讨在疫情处置中对接触者进行胸片随访的意义。方法 2016年3月17日至4月17日,北京市大兴区某职业培训学校共发现活动性肺结核患者21例,构成聚集性结核病疫情。疫情发生后,对全校3490名师生进行了结核菌素（PPD）皮肤试验及胸部X线摄影筛查。对筛查发现的65例胸片异常者进行了3次痰涂片及2次痰分枝杆菌培养,确诊患者39例;对313例单纯PPD皮肤试验强阳性者,进行预防性化学治疗。为及时发现续发患者,确定疫情3个月后对全校除活动性肺结核患者以外的师生进行第1次胸部X线摄影随访。此后,疫情处置中又开展了3次胸部X线摄影随访,间隔时间分别为3个月、6个月、8个月。在每次随访时,打印出本次确诊患者胸片,与其以往胸片（电子版）进行比较,观察其肺内病灶是否有变化或遗漏,并做好相关记录。采用SPSS 18.0软件对数据进行统计学分析,计数资料的比较采用χ 2检验,以P〈0.05为差异有统计学意义。 结果 至结案时,本次疫情共发现活动性肺结核患者162例。疫情发生时患者的发现率为1.7%（60/3490）,随后进行的4次胸片随访的患者检出率分别为1.6%（50/3031）、0.7%（19/2650）、0.8%（15/1860）和0.2%（2/1134）。疫情发生3个月后第1次胸部X线摄影随访时,活动性肺结核患者的检出率明显高于其他3次随访,差异有统计学意义（χ 2=23.73,P〈0.05）。4次胸部X线摄影随访共确诊延迟发现患者17例,在疫情发生3个月后进行第1次胸部X线摄影随访时发现15例,在第2次和第3次胸部X线摄影随访时,延迟发现患者均为1例,第4次胸部X线摄影随访时无延迟发现患者。延迟发现率分别为30.0%（15/50）、5.3%（1/19）、6.7%（1/15）和0.0%。第1次胸部X线摄影随访时患者的延迟发现率明显高于其他3次,差异有统计学意义（χ 2=7.89,P〈0.05）。 结论 学校聚集性结核病疫情发生后进行胸片随访,尤其在疫情发生3个月后,可及时发现新发患者及遗漏诊断患者,有效控制疫情发展,在较为严重的学校结核病疫情处置过程中是一种非常有效的手段。

Objective To analyze the epidemic of clustered tuberculosis （TB） in a school setting, and to explore the significance of chest X-ray follow-ups in the disposition of TB epidemic outbreak. Methods A total of 21 patients with active TB were found in a vocational training school in Daxing District, Beijing from March 17th to April 17th 2016, which was an epidemic of clustered TB outbreak. After the outbreak, 3490 teachers and students received tuberculin （PPD） skin test and chest X-ray screening, and then 3 sputum smears and 2 sputum mycobac-terium culture examinations were performed on each of the 65 cases who appeared to have abnormal chest X-ray results, 39 cases were diagnosed with TB; 313 cases with strongly PPD positive reactions were treated with preventive chemotherapy. The first chest X-ray follow-up was made for the school teachers and students （except for the confirmed patients with active pulmonary TB） 3 months after the disease outbreak. Thereafter 3 chest X-ray follow-ups were carried out and the intervals were 3, 6 and 8 months respectively. Chest radiographs of newly diagnosed patients were printed out during each follow-up and compared with their previous chest imaging data so as to observe whether there were any changes or omissions in the lung lesions, and the relevant records were made. SPSS 18.0 software was used for data analysis,the comparison of count data rate was done by χ2 test and P〈0.05 was regarded as statistically significant. Results A total of 162 cases with active TB were found in the outbreak. The detection rate was 1.7% （60/3490） when the epidemic occurred, and the detection rates of the 4 follow-ups were 1.6% （50/3031）, 0.7% （19/2650）, 0.8% （15/1860） and 0.2% （2/1134） respectively. The detection rate in the first follow-up （1.6%） was significantly higher than that of the other 3 follow-ups （that was 0.7%, 0.8% and 0.2%） （χ2=23.73, P〈0.05）. Seventeen cases were delayed to be detected in the 4 follow-ups, of which 15 cases were found in the first follow-up, while 1 case was found in the second and third follow-up respectively, no delayed cases were found in the fourth follow-up. So the detection rates of the delayed cases in the 4 follow-ups were 30.0% （15/50）, 5.3% （1/19）, 6.7% （1/15） and 0.0% respectively, and the detection rate of the delayed cases in the first follow-up was significantly higher than the other 3 follow-ups （χ2=7.89,P〈0.05）. Conclusion It is able to detect the new cases and omissive cases timely in the follow-ups after the outbreak of tuberculosis, especially 3 months after the outbreak, which is effective for the control of tuberculosis epidemic in a school setting.