密切接触者PPD强阳性率在学校结核病暴发风险评估中的应用价值

目的 对大连市登记的散发学生肺结核患者密切接触者进行回顾性分析,探究PPD强阳性率在学校结核病暴发风险评估中的应用价值.方法 对2010年12月至2013年12月间录入全国结核病管理信息系统中的大连市散发学生肺结核患者及其密切接触者资料进行收集和分析,共纳入散发肺结核患者228例,并对其9863名密切接触者随访12个月.观察涂阳和涂阴患者的密切接触者发病情况与PPD强阳性率(PPD硬结平均直径≥15 mm)分布,采用ROC曲线获取结核病暴发和续发患者的PPD强阳性率的截断值.结果 228例散发肺结核患者中,涂阳肺结核39例,其密切接触者发生“偶然聚集”和“结核病暴发”的发生率分别为17.9％ (7/39)和10.3％ (4/39);涂阴肺结核189例,其密切接触者发生“偶然聚集”和“结核病暴发”的发生率均为7.9％ (15/189);两者比较,x2=0.60、0.23,P值均＞0.05.涂阳患者密切接触者的强阳性率均值为(16.0±0.8)％;涂阴肺结核患者密切接触者的强阳性率均值为(15.3±0.9)％,两组间差异无统计学意义,x2=2.41,P＞0.05.大连市入学新生的PPD强阳性率为(6.5±0.5)％,与发生结核病疫情的不同级别(无聚集、偶然聚集和聚集性暴发)的PPD强阳性率均值的组间差异有统计学意义,x2=26.14,P＜0.01.将随访期12个月内发生续发患者作为诊断标准,绘制PPD强阳性率ROC曲线,特异度为85.0％,敏感度为70.0％,曲线下面积为0.78,截断值为25.5％.将结核病暴发作为诊断标准,绘制PPD强阳性率ROC曲线,特异度和敏感度均为78.0％,曲线下面积为0.81,截断值为21.5％.结论 涂阳和涂阴患者具有相同的引发结核病暴发事件的风险.高暴露群体PPD强阳性率超过21.5％是产生续发患者的预警指标,提示密切接触者具有发病可能,应及时进行干预.     

一起校园结核病暴发事件的回顾性分析

目的 对一起学校结核病暴发事件进行回顾性分析,探讨疫情处置的最佳原则与方法.方法 对发生结核病暴发的大连市一所中学的整个初3年级229名学生进行胸部X线摄影和PPD筛查.描述疫情的三间分布特征、评价暴露水平、PPD与续发患者的关系.结果 根据与传染源的接触密切程度关系,将暴露分为4个水平:1级暴露人群为传染源所在班级接触者,PPD强阳性率为74.0％(37/50);2级暴露人群为与1班相邻且经常在一个教室上课的接触者,PPD强阳性率为58.5％(24/41);3级暴露人群为位于同一楼层但不与传染源同在一教室上课的接触者,PPD强阳性率为31.8％(21/66);4级暴露人群为既不在同一楼层上课,又不在同一教室上课的其他班级接触者,PPD强阳性率为12.7％(9/71).1级和2级暴露人群的结核病罹患率分别为16.0％(8/50)和2.4％(1/41),x2=4.65,P＜0.05.按照首次密切接触者筛查PPD试验结果统计:PPD硬结平均直径≥15 mm与＜ 15 mm两组的结核病罹患率分别为13.3％(2/15)和17.1％(6/35),x2=0.11,P＞0.05;按照3个月随诊密切接触者PPD试验结果统计:PPD硬结平均直径≥15 mm和＜15 mm的结核病罹患率分别为16.2％(6/37)和15.4％(2/13),x2=0.00,P＞0.05.对于本次疫情,即使对PPD硬结平均直径≥15 mm者(共计15名)全部进行预防,理论上仅能对22.2％(2/9)的续发患者进行前期干预.结论 在结核病暴发中,结核分枝杆菌高暴露者具有较高的发病风险;续发患者与PPD是否强阳性无关.建立风险评估机制是防止学校聚集性疫情发生的有效手段.     

西昌市1起学校结核病疫情的调查分析

目的对西昌市某镇中心小学1起结核病疫情进行调查分析,为学校结核病防控工作提供参考依据。方法对报告病例开展流行病学个案调查,对密切接触者进行PPD试验(结核菌素实验)筛查,PPD阳性、强阳性者进一步做DR胸片、痰涂片查抗酸杆菌,确诊的结核病患者纳入规范抗结核治疗,并严格实行休复学管理。对患者15岁以上家属做DR胸片、痰涂片查抗酸杆菌检查,确诊患者纳入规范抗结核治疗。结果对129名密切接触者进行PPD筛查,强阳性率为1.55%、阳性率为11.63%;PPD强阳性、阳性者进一步检查排除肺结核。通过近半年定期随访检查,无新病例发生。患者家属15岁以上的经检查后排除肺结核。结论该起疫情来自于家庭内部感染,因就诊及时,疫情处置迅速、规范,未造成学校聚集性疫情的发生。     

2018年济南市学校肺结核患者密切接触者筛查结果分析

目的调查2018年济南市学校肺结核患者密切接触者的筛查情况,对全市学校肺结核疫情和处置情况进行分析。方法建立2018年济南市学校肺结核的发病情况和处置结果数据库,包括济南市市、县两级监测到《传染病报告信息管理系统》中报告的患者、学校方告知患者及外地单位反馈的学校患者。2018年全市共发现学生或教师肺结核患者197例,除去实习、毕业或近期接受过筛查等原因的10例患者,对187例肺结核患者开展个案流行病学调查,确定密切接触者共11617名。对其中24例病原学阳性肺结核患者确定密切接触者2138名,实际筛查2104名;163例病原学阴性及无病原学结果的肺结核患者确定密切接触者9479名,实际筛查9384名。密切接触者采用全市统一配发的卡介菌纯蛋白衍生物(BCG-PPD)试剂进行结核菌素皮肤试验(简称"PPD试验")筛查。结果2018年济南市学校肺结核患者以大学生为主81.28%(152/187)。11488名密切接触者的PPD试验结果中,阴性8898名(77.45%),一般阳性1434名(12.48%),中度阳性651名(5.67%),强阳性505名(4.40%)。24例病原学阳性患者的密切接触者PPD试验强阳性率(7.41%,156/2104)明显高于163例非病原学阳性患者密切接触者PPD试验的强阳性率(3.72%,349/9384),差异有统计学意义(χ^2=55.84,P<0.001)。通过筛查共发现肺结核患者31例。结论通过对学校肺结核患者密切接触者的筛查,可发现部分结核病患者;落实肺结核患者密切接触者的结核病筛查工作,可减少结核病在学校中的传播。     

2009-2011年绵竹市中小学生结核菌素试验结果分析

目的 了解绵竹市中、小学生结核感染情况,为学校结核病防治工作提供依据.方法 2009-2011年对绵竹市在校中、小学生进行结核菌素(PPD)试验,并对试验结果强阳性的学生进行胸部X线及痰涂片检查.结果 2009-2011年受检学生63 018人,总体阳性率、强阳性率分别为38.19％、1.31％,不同年度PPD阳性率、强阳性率间差异无统计学意义,农村学生PPD阳性率、强阳性率高于城区学生,受检男生PPD阳性率、强阳性率大于女生,随年级增长对PPD制剂的反应增强,卡痕阳性者PPD阳性率大于卡痕阴性者,强阳性学生中发现肺结核12例,筛查患病率0.02％.结论 PPD试验结果与有关报道接近,筛查发现的学生中肺结核患者占报告的学生发病数的2/3,提示学校仍是结核病防控工作的重点,对在校学生进行PPD试验筛查结核病非常必要,应提高筛查覆盖率.     

铜陵市某精神疾病专科医院结核病聚集性疫情调查处置

目的调查处置铜陵市某精神疾病专科医院聚集性疫情,为今后类似疫情处置提供参考。方法对2015年安徽铜陵市某专科医院发生的结核病聚集性疫情开展现场流行病学调查和密切接触者筛查,诊断方法包括结核菌素(PPD)皮肤实验、X线胸片、痰涂片检查。结果疫情共发现肺结核病例12例,均为菌阴肺结核,A病区6例,罹患率6.12%; B病区6例,罹患率8.11%; A病区密切接触者PPD强阳性率为8. 70%,B病区密切接触者PPD强阳性率为24.66%,预防性服药率19.04%。结论此次疫情发生由于未早期发现、隔离并治疗肺结核患者,专科医院未及时开展密切接触者筛查及消毒措施,未做好患者管理控制工作。早期发现、隔离并治疗结核病患者,把好患者进出关口,加强结核病相关知识的培训等措施,是预防控制精神疾病专科医院发生的结核病疫情的关键。     

古蔺县某初级中学结核病聚集性疫情处置与医学观察结果分析

目的对2018-2019年期间古蔺县某初级中学发生的一起结核病聚集性疫情进行调查处置分析,以期为学校结核病防控工作提供参考,为疾控机构相关疫情处置提供借鉴。方法开展学校结核病流行病学调查和指示病例个案调查,对密切接触者和一般接触者进行症状、PPD试验和X光胸片筛查,对疑似患者进一步开展CT和痰涂片检查。结果对该校初三(4)班指示病例的67名密切接触师生进行筛查,发现可疑患者11例,经专家确诊肺结核5例,其中涂阳2例;扩大筛查范围时对初三年级的454名一般接触师生进行筛查,发现可疑患者47例,经专家确诊肺结核6例,其中涂阳病例1例。医学观察发病2例,其中涂阳1例,此次疫情共发现肺结核患者14例。指示病例班级发现涂阳肺结核4例(包括指示病例),其中2例与指示病例座位相邻,1例与指示病例同宿舍,提示存在相互传播的可能。结论延迟发现传染源并归口治疗可能是造成疫情传播的主要原因,及时规范开展密切接触者筛查、诊断和治疗有利于防止疫情的进一步扩大,加强学校师生及其学生家长结核病防治知识宣传提高自我辨识能力对学校结核病防控具有重要意义。     

大中专院校学生结核感染发病情况调查分析

目的 对大中专学生结核感染与发病情况进行总结分析，为进一步加强高校结核病控制提供决策依据。方法 新生入学时做结核菌素（PPD）试验和胸透，PPD强阳性（注射局部硬结直径≤20mm）者枉知情同意基础上开展F胰预防性治疗，并对治疗与未治疗组进行发病情况的追踪观察及对比分析,以了解预防性治疗的实际效果.结果 大中专结核感染情况较严重,结素阳性率平均74.2%,强阳性水平均12.6%,高校学生肺结核平均发病率117.93/10万,结素强阳性未治疗者肺结核年发病率高达614.54/10万,是结素阴性及一般阳性者（67.03/10万）的9.2倍.结论 大中专学生结核感染发病情况较严重,是结核暴发浒的严重隐患之一,加强大中专院校结核病控制乃当务之急;新生入学体验,学生中结核病防治基本知识的宣传普及,结素强阳性者预防性治疗、因症就诊为病人发现方式、肺结核病人定点规范诊治，是控制大中专院校结核病疫情的有效措施。     

2013年四川省彭山县结核病筛查结果分析

目的了解四川省彭山县结核病流行和防治现状,为下一步制定全县结核病防治规划提供参考依据。方法2013年对彭山县11 257人进行结核病筛查试验(结核菌素试验Purified Protein Derivative,PPD),筛查发现的强阳性者进一步进行拍摄X线胸片和痰菌涂片检查。结果 11 257名受检者中总共筛查出198(男108,女90)例强阳性可疑对象,进一步进行拍摄X线胸片和痰涂片检查,确诊5(男3,女2)例活动性肺结核患者,肺结核患病率44.42/10万,其中筛查前已知患者2例,筛查时新发现患者3例。结论对PPD试验阳性者进行胸透、查痰、拍摄X线胸片,可有效发现既往和新发活动性肺结核患者,适于大面积结核病普查时应用以提高效率。     

2009-2012年中央财经大学入学新生PPD试验结果分析

目的 了解中央财经大学新生PPD试验结果，为学校结核病防治工作提供可靠的科学依据。方法收集中央财经大学2009-2012年入学本科新生共计9702名的结核菌素纯蛋白衍生物(TB-PPD)试验结果，并采用描述性统计分析方法分析结果。组间比较运用χ²检验，P<0.05为差异有统计学意义。 结果 全部新生PPD试验强阳性率为6.02%(584/9702)，其中，男生的强阳性率为4.04%(145/3587)，女生为7.18%(439/6115)，差异有统计学意义（χ²=39.32，P<0.05）。2010年PPD试验强阳性率最高，为10.44%（233/2231）；2009年、2012年和2011年次之，强阳性率分别为5.43%（136/2505）、4.75%(116/2442)和3.92%（99/2524）。4年间新生体检共检出肺结核患者14例，检出率为0.14%（14/9702）。14例肺结核患者中，6例PPD试验强阳性。 结论 在高校新生开展PPD普查，是发现结核病的必要辅助方法，加强在校学生结核病筛查，是控制结核病在高校传播流行的有效措施。     

HIV／AIDS患者肺结核患病调查分析

目的了解HIV感染者和艾滋病病人合并肺结核状况,为HIV/TB双重感染防治工作提供基础资料。 方法对11个县、区能随访到的HIV感染者和艾滋病病人进行问卷调查,同时测CD4细胞计数、PPD试验、正位X线胸片、抗酸杆菌痰涂片显微镜检查。 结果622例被调查者的肺结核患病率为3.9%,双重感染病人的PPD阳性率为54.2%;HIV/AIDS患者的PPD阳性率为19.0%,随着CD4细胞计数的增加,PPD阳性率升高。 结论HIV/AIDS病人肺结核患病率高于普通人群,PPD阳性率低于普通人群。CD4细胞越少,PPD阳性率越低。     

T-SPOT.TB与PPD在消化系统结核感染鉴别诊断中的价值

目的评估快速T细胞计数体外酶联免疫斑点技术(T-ELISPOT.tuberculosis,T-SPOT.TB)与PPD试验在消化系统结核感染的诊断价值。方法回顾性分析2011年6月-2013年7月于南京军区南京总医院消化内科收治的60例患者,其中14例确诊为结核感染的患者,46例为非结核感染的消化系统疾病患者,抽取患者外周血送检,T-SPOT.TB与PPD试验结果的准确性进行比较。结果 14例确诊结核感染患者,46例非结核感染的患者,T-SPOT.TB的灵敏度与PPD试验相近,差异无统计学意义(78.6%vs71.4%,P=1.000);T-SPOT.TB的特异性显著大于PPD试验(91.3%vs 69.6%,P=0.009);T-SPOT.TB阳性预测率显著大于PPD试验(73.3%vs 41.7%,P=0.001);T-SPOT.TB阴性预测率与PPD试验相近,差异无统计学意义(93.3.%vs 91.1%,P=1.000)。T-SPOT.TB与PPD试验在诊断消化系统结核感染方面有较好的吻合性(K=0.341,P=0.018)。结论 T-SPOT.TB应用于消化系统感染的诊断,尤其适合PPD阳性的疑似消化系统结核感染患者的鉴别诊断。     

酶联免疫斑点试验在菌阴肺结核诊断中的价值

目的探讨酶联免疫斑点检测技术(enzyme-linked immunospot assay,ELISPOT)(T-SPOT.TB)在菌阴肺结核诊断中的应用价值。方法应用T-SPOT.TB试剂盒对55例菌阴肺结核(A组)和36例其他肺部疾病(B组)患者的外周血中Mtb特异性T淋巴细胞进行检测,同时对两组患者进行PPD试验、血清结核抗体(Mtb-AB)检测。结果A组T-SPOT.TB的阳性率为89.1%(49/55),要明显高于B组的19.4%(7/36)(χ2=44.59,P<0.001)。在A组,T-SPOT.TB的阳性率要明显高于PPD试验[36.4%(20/55)]、Mtb-AB[52.7%(29/55)]及PPD试验+Mtb-AB的阳性率[23.6%(13/55)],(χ2=12.13,χ2=7.08,χ2=21.54,P值均<0.01)。T-SPOT.TB在B组中的阴性率为80.6%(29/36),较PPD试验[86.1%(31/36)]及Mtb-AB阴性(63.9%,23/36)和PPD+Mtb-AB检测方法的阴性率[88.9%(32/36)]经检验,差异无统计学意义(χ2=0.39,χ2=2.69,χ2=0.41,P值均>0.05)。结论T-SPOT.TB检测特异度和敏感度要优于PPD试验及Mtb-AB的检测,可用于菌阴肺结核的辅助诊断,具有一定的临床推广使用的价值。     

1350例PPD试验阳性患者纤维支气管镜刷片找结核菌预测分析

目的研究PPD试验阳性患者阳性程度与其纤支镜刷片找结核菌阳性率预测价值。方法对我院2001年8月至2009年8月收治的1350例PPD试验阳性患者纤支镜刷片找结核菌结果进行回顾性调查研究,及将PPD试验阳性分为弱阳性、阳性、强阳性、强阳性合并水泡四组,观察其四组纤支镜刷片找结核菌阳性率。结果1350例PPD试验阳性患者中254例弱阳性患者纤支镜刷片结核菌阳性率为1．18％;684例阳性患者纤支镜刷片结核菌阳性率为3．51％;380例强阳性患者纤支镜刷片结核菌阳性率为15．26％;32例强阳性合并水泡患者纤支镜刷片结核菌阳性率为56．25％。结论PPD试验强阳性合并水泡患者纤支镜刷片找结核菌阳性率较高,对I}缶床选择纤支镜诊治肺结核病有较高临床意义。     

Tuberculosis in renal transplant recipients

Tuberculosis (TB) has been described in kidney transplant recipients as an infection with predominantly pulmonary involvement. We report the impact of TB in kidney transplantation. Clinical records of adult kidney recipients, transplanted between 1 January 1986 and 31 December 1995 were analyzed for sex, age, graft origin, immunosuppressive therapy, TB sites, diagnostic methods and concomitant infections. Annual incidence, mean time of onset, relation to rejection treatment, tuberculin skin test (PPD) and outcome were analyzed. Patients with a history of TB or graft loss in the first month were excluded. TB was diagnosed in 14 of 384 (3.64%). Mean age at transplantation was 35 years. Twelve of these received the graft from a living donor. All had triple immunosuppression with cyclosporine. Ten had pulmonary TB, three extrapulmonary infection and one disseminated disease. In 13 cases an invasive diagnostic procedure was performed. Mycobacterium tuberculosis cultures were positive in all cases; microscopy revealed acid-fast bacilli (AFB) in 6, and adenosine deaminase was elevated in CSF and pleural effusion in 2. Annual incidence varied from 0% to 3.1%. At the time of TB presentation 8 patients had other concomitant infections (cytomegalovirus, nocardia, Pneumocystis carinii, disseminated herpes simplex virus). Median time of onset was 13 months. Diagnostic results became available post-mortem in 2 cases, and one had TB in a failing allograft. TB was treated with 4 drugs including rifampin in 10 patients. Cyclosporine was discontinued in one, lowered in one and increased in 8. During treatment 5 patients had rejection episodes. At 1 year, graft survival was 72.7% and patient survival 90.9%. TB was more prevalent when recipient and donor were both PPD positive. In summary: although TB is a growing threat in the transplant setting, early and aggressive diagnosis with meticulous monitoring of immunosuppression allows a successful outcome for both patient and graft. Optimal prophylaxis guidelines have yet to be completely defined.     

联合检测结素试验和血清抗结核抗体对成人肺结核诊断预测价值:Bayesian分析

目的　探讨结素试验及血清抗结核抗体对成人肺结核诊断的预测价值。方法 经细菌学、病理组织学或细胞学确诊的 134例肺结核病、109例胸部肿瘤及 51例肺部感染成人患者接受结素试验及血清抗结核抗体检查。比较结素试验不同硬结直径作阳性筛查标准及与血清抗结核抗体的不同组合对结核病诊断的价值。阳性预测价值和阴性预测价值的估计应用Bayes公式。结果 结素试验与血清抗结核抗体检测,两者结合可提高诊断价值,若以结素试验硬结直径≥15mm或血清抗结核抗体阳性作为阳性筛查标准 (标准 1),则阴性预测价值最大 ;若以结素试验硬结直径≥20mm及血清抗结核抗体阳性作为阳性筛查标准 (标准 2),则阳性预测价值最大。若就诊患者中肺结核患病率分别为:0.5 %,5 %,10 %,30 %,60 %时,标准 1的阴性预测价值分别为:0.999,0.987,0.972,0.901,0.723;标准 2的阳性预测价值均为 1.000。结论 在结核高感染地区,联合检测结素试验及血清抗结核抗体对诊断成人结核病仍有辅助价值。结素试验硬结直径小于 15mm且血清抗结核抗体阴性对排除结核病有帮助;结素试验硬结直径≥ 20mm且血清抗结核抗体阳性,对确诊结核病有帮助。     

Tuberculosis exposure of patients and staff in an outpatient hemodialysis unit

BACKGROUND: Patients receiving hemodialysis are generally considered to be at increased risk of developing tuberculosis (TB). We evaluated a 13-station chronic outpatient hemodialysis unit associated with a community hospital in northern California. Within 6 months, there were 2 incident source cases in the unit of active smear positive pulmonary tuberculosis; the first in a health care worker (HCW), diagnosed April 3, 1998, and the second in a patient undergoing dialysis treatment in October 1998. We describe the cases; the evaluation of exposures; and the institution of an intentional prospective TB control plan, designed specifically for the unique hemodialysis setting. METHODS: We evaluated 23 HCWs twice and 89 patients undergoing hemodialysis treatment who were exposed to case 1 and 38 patients who were exposed to case 2. All 23 HCWs had documented prior negative Sierbert purified protein derivative of tuberculin (PPD) status and were retested at 12 weeks after exposure. None of the patients had documentation of PPD status. All of the patients were skin-tested initially with use of the 2-step method, and those with positive test results were offered isoniazid (INH). RESULTS: One of the 23 HCWs' negative baseline PPD skin test status converted after exposure to case 1, and none of the remaining 22 converted after exposure to case 2. Twelve of 89 exposed patients with no prior skin test record had positive results for PPD after initial testing with the 2-step method. Three of the 12 (25%) patients were treated with INH at the discretion of their attending nephrologist. The 77 patients with negative results for PPD still had negative test results when retested at 3 months. None of 38 patients who underwent dialysis on the same schedule as source case 2 had a converted PPD test. Restriction fragment length polymorphism on TB isolates from both source cases ultimately showed them to be unrelated strains. CONCLUSION: Our experience with these exposures suggests that TB screening of patient populations undergoing renal dialysis-though they have intrinsic high anergy rates-is advisable with a designed prospective plan before any inadvertent and/or repetitive exposure of that population to active TB. A planned intentional TB control program increases HCW awareness of TB, establishes baselines for evaluation, decreases "panic" in the event of subsequent exposures, and emphasizes the rationale for preventive therapy.     

The booster phenomenon in two-step tuberculin testing of employees in a community hospital]

A study was made to clarify to what degree the booster phenomenon was present when the employees in a community hospital in Japan received two-step tuberculin testing (PPD). Of the seventy-five employees, most of all BCG-vaccinated subjects, twenty-three showed strongly positive of more than 30 mm of induration at the first test (PPD/T1), and the remaining fifty-two subjects received a second (PPD/T2) after 2 weeks. The second PPD showed a marked increase in reactivity, sixteen subjects newly became strongly positive and six of eight who were initially PPD negative (< 10 mm) were converted positive, and the mean reaction size changed from 14.7 +/- 5.6 mm (PPD/T1) to 31.5 +/- 15.5 mm (PPD/T2). The degree of boosting, measured by the change in millimeters induration size between PPD/T1 and PPD/T2 (PPD/T2-PPD/T1), was correlated with neither the size of PPD/T1 nor the age of the study participants, and was not associated with the difference of the position in the hospital. Thus, we could not explain the factor why such a marked boosting was observed in this study. However, these results indicated that the two-step tuberculin testing is an essential means of distinguishing new tuberculous infection from booster phenomenon. We agree with the current recommendation for routine two-step testing of new employees in the hospital.     

Transmission of Mycobacterium tuberculosis among employees in a US government office, Gaborone, Botswana.

SETTING: A US government office located in Botswana where two office employees, one negative and one positive for the human immunodeficiency virus (HIV), were diagnosed with pulmonary tuberculosis (TB) in January 1998. One employee had been symptomatic with untreated laryngeal TB for 8 months. OBJECTIVE: To determine the extent of and risk factors for TB transmission in the office. METHODS: Office contacts were interviewed and a tuberculin skin test (TST) was performed. A positive TST was defined as > or = 10 mm induration for employees from countries where TB is highly endemic, and as > or = 5 mm induration for those from low prevalence counties. RESULTS: Of 79 office contacts investigated, 54/57 (94.7%) born in high TB prevalence countries had a positive TST compared with 4/22 (18.2%) from low prevalence countries (RR 5.1, 95% CI 2.1-12.7, P < 0.001). Of 20 US-born contacts, three (15%) had documented TST conversion, two of whom were co-workers of the employee with laryngeal TB. Isolates of Mycobacterium tuberculosis from the TB cases had matching DNA fingerprints. CONCLUSION: Delayed diagnosis in a setting of high TB prevalence may have contributed to transmission within a US government office located in Botswana. Transmission may have been underestimated due to the high background prevalence of tuberculous infection in the population. Recent tuberculous transmission to persons living with HIV infection may be playing an important role in the escalating TB epidemic in Africa.     

沧州地区高中在校生PPD反应的流行病学调查

目的调查沧州地区高中学生结核菌感染的现状,分析影响结核菌素皮试结果的多方面因素,进行肺结核患病筛查并针对调查结果提出合理化建议,采取防控措施,降低肺结核感染率。方法确定受试人群,为我沧州地区部分县市(包括海兴县、盐山县、河间市、沧县及沧州市区某中学)高中在校生共8560例,年龄15~19周岁。采用武汉生物公司出品的结核菌素试剂,剂型为1ml,50IU。于受试者前臂掌侧远端1/3中央皮内注射结核菌素5IU,进行PPD皮试检查,72 h观察结果,取反应硬结横径与竖径的平均值记录。结果PPD中度以上阳性者为(877)例,其中,强阳性为439例,确诊肺结核患者51例,中强阳性率为(10.24%),患病率(0.60%)。男性高于女性。各年级组比较阳性率及患病率均有明显差异,具有统计学意义(P0.05)。结论高中生PPD反应中强阳性者为结核病的高发人群,应作为结核病预防性治疗对象。