Xu Zuhui, Liu Haican, Liu Yanping, Tang Yi, Tan Yunhong, Hu Peilei, Zhang Chuanfang, Yang Chongguang, Wan Kanglin, Wang Qiaozhi
Xiangya School of Public Health, Central South University, Changsha, 410078, People's Republic of China.
Tuberculosis Control Institute of Hunan Province, Changsha, 410013, People's Republic of China.
Infect Drug Resist. 2022 Sep 2;15:5149-5160. doi: 10.2147/IDR.S371772. eCollection 2022.
Tuberculosis (TB) seriously threatens individual and public health. Recently, TB outbreaks in schools have been reported more frequently in China and have attracted widespread attention. We reported three TB outbreaks in high schools in Hunan Province, China.
When a tuberculosis patient was reported in a school, we carried out field epidemiological investigations, including tuberculin skin testing (TST), chest X-ray (CXR) and laboratory test for all close contacts, and whole-genome sequencing (WGS) analyses to understand the transmission patterns, the causes and the risk factors for the outbreaks, thereby providing a foundation for the control of TB epidemics in schools.
A total of 49 students with TB patients were identified in the three schools where TB outbreaks occurred, including nine patients in School A, 14 patients in School B, and 26 patients in School C. In Schools A, B and C, the putative attack rates in the classes of the index case were 13.8% (8/58), 7.6% (5/66), and 40.4% (21/52), while the putative attack rates of expanding screening in the school were 0.3% (1/361), 0.2% (9/3955), and 0.2% (5/2080), respectively. Thirteen patients had patient delay, with a median delay interval of 69 days (IQR 30.5-113 days). Twelve patients had a healthcare diagnostic delay with a median delay interval of 32 days (IQR 24-82 days). Phylogenetic analysis of culture-positive patients revealed that most of them shared a small genetic distance (≤12 SNPs), with three separate genetic clusters (including one MDR-TB genomic cluster), indicating the recent transmission of strains.
This combination of field investigation and WGS analysis revealed the transmission of three TB outbreaks in schools. Reinforced implementation is needed to improve timely case finding and reduce diagnosis delay in routine TB control in the school population.
结核病严重威胁个人和公众健康。近年来，中国学校结核病暴发报告日益增多，受到广泛关注。我们报告了中国湖南省3起高中结核病暴发疫情。
学校报告结核病患者后，我们开展现场流行病学调查，包括对所有密切接触者进行结核菌素皮肤试验（TST）、胸部X线检查（CXR）及实验室检测，并进行全基因组测序（WGS）分析，以了解疫情的传播模式、原因及危险因素，从而为学校结核病疫情防控提供依据。
在发生结核病暴发疫情的3所学校共发现49例结核病学生患者，其中A校9例，B校14例，C校26例。在A、B、C三所学校，首例病例所在班级的假定罹患率分别为13.8%（8/58）、7.6%（5/66）和40.4%（21/52），而学校扩大筛查的假定罹患率分别为0.3%（1/361）、0.2%（9/3955）和0.2%（5/2080）。13例患者存在患者延误，中位延误时间为69天（四分位间距30.5 - 113天）。12例患者存在医疗机构诊断延误，中位延误时间为32天（四分位间距24 - 82天）。对培养阳性患者的系统发育分析显示，大多数患者的基因距离较小（≤12个单核苷酸多态性），有3个独立的基因簇（包括1个耐多药结核病基因组簇），表明菌株为近期传播。
现场调查与WGS分析相结合揭示了3起学校结核病暴发疫情的传播情况。在学校人群的常规结核病防控中，需要加强措施以改善病例的及时发现并减少诊断延误。
