Braden C R
Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
Clin Infect Dis. 1995 Sep;21(3):565-70. doi: 10.1093/clinids/21.3.565.
A search for the source of infection for four children with tuberculosis (TB) identified a university student with cavitary and laryngeal TB. An investigation was conducted at the university, including tuberculin skin test (TST) screening and the use of questionnaires, chest radiographs, and DNA fingerprint analyses of Mycobacterium tuberculosis isolates. Six students with active TB were identified. All were linked to the source case. TSTs were positive for 22.4% of 419 students who had contact with the source case vs. 3.6% of 1,306 students without contact. The odds of a positive TST increased to 9.0 with 80 hours of classroom contact. Infectiousness increased significantly in the last of three semesters during which the source case was symptomatic (RR of a positive TST in classmates, 4.8; 95% CI, 1.8-11.8). TST conversions were documented in 23 students; eight had, at most, 5 hours of classroom contact. The source case was highly infectious; transmission following only a few hours of exposure was documented. Her infectiousness increased as her clinical course progressed. This report illustrates the potential infectiousness of TB cases and demonstrates important aspects of tuberculosis control.
对4名患结核病（TB）儿童的感染源进行追查，发现一名患有空洞性和喉结核的大学生。在该大学开展了一项调查，包括结核菌素皮肤试验（TST）筛查，并使用问卷、胸部X光片以及对结核分枝杆菌分离株进行DNA指纹分析。确定了6名活动性结核学生。所有这些学生均与源头病例有关联。与源头病例有接触的419名学生中，22.4%的TST呈阳性，而未接触的1306名学生中这一比例为3.6%。课堂接触80小时后，TST呈阳性的几率增至9.0。在源头病例出现症状的三个学期中的最后一个学期，传染性显著增加（同学中TST呈阳性的相对危险度为4.8；95%可信区间为1.8 - 11.8）。记录到23名学生的TST发生转变；其中8名学生课堂接触时间最多为5小时。源头病例具有高度传染性；记录到仅经过数小时接触就发生了传播。随着其临床病程进展，其传染性增加。本报告说明了结核病例的潜在传染性，并展示了结核病控制的重要方面。
