Transmissibility of tuberculosis among school contacts: an outbreak investigation in a boarding middle school, China

Epidemiological Characteristics and Spatiotemporal Clustering of Pulmonary Tuberculosis Among Students in Southwest China From 2016 to 2022: Analysis of Population-Based Surveillance Data

Background

Pulmonary tuberculosis (PTB), as a respiratory infectious disease, poses significant risks of covert transmission and dissemination. The high aggregation and close contact among students in Chinese schools exacerbate the transmission risk of PTB outbreaks.

Objective

This study investigated the epidemiological characteristics, geographic distribution, and spatiotemporal evolution of student PTB in Chongqing, Southwest China, aiming to delineate the incidence risks and clustering patterns of PTB among students.

Methods

PTB case data from students monitored and reported in the Tuberculosis Information Management System within the China Information System for Disease Control and Prevention were used for this study. Descriptive analyses were conducted to characterize the epidemiological features of student PTB. Spatial trend surface analysis, global and local spatial autocorrelation analyses, and disease rate mapping were performed using ArcGIS 10.3. SaTScan 9.6 software was used to identify spatiotemporal clusters of PTB cases.

Results

From 2016 to 2022, a total of 9920 student TB cases were reported in Chongqing, Southwest China, with an average incidence rate of 24.89/100,000. The incidence of student TB showed an initial increase followed by a decline, yet it remained relatively high. High school students (age: 13-18 years; 6649/9920, 67.03%) and college students (age: ≥19 years; 2921/9920, 29.45%) accounted for the majority of student PTB cases. Patient identification primarily relied on passive detection, with a high proportion of delayed diagnosis and positive etiological results. COVID-19 prevention measures have had some impact on reducing incidence levels, but the primary factor appears to be the implementation of screening measures, which facilitated earlier case detection. Global spatial autocorrelation analysis indicated Moran I values of >0 for all years except 2018, ranging from 0.1908 to 0.4645 (all P values were <.05), suggesting strong positive spatial clustering of student PTB cases across Chongqing. Local spatial autocorrelation identified 7 high-high clusters, 13 low-low clusters, 5 high-low clusters, and 4 low-high clusters. High-high clusters were predominantly located in the southeast and northeast parts of Chongqing, consistent with spatial trend surface analysis and spatiotemporal clustering results. Spatiotemporal scan analysis revealed 4 statistically significant spatiotemporal clusters, with the most likely cluster in the southeast (relative risk [RR]=2.87, log likelihood ratio [LLR]=574.29, P<.001) and a secondary cluster in the northeast (RR=1.99, LLR=234.67, P<.001), indicating higher reported student TB cases and elevated risks of epidemic spread within these regions.

Conclusions

Future efforts should comprehensively enhance prevention and control measures in high-risk areas of PTB in Chongqing to mitigate the incidence risk among students. Additionally, implementing proactive screening strategies and enhancing screening measures are crucial for early identification of student patients to prevent PTB outbreaks in schools.

Epidemiological characteristics and influencing factors of tuberculosis aggregation in schools in Wuhan, China during 2017-2022

Background

Wuhan is located in the hinterland of China, in the east of Hubei Province, at the intersection of the Yangtze River and Hanshui River. It is a national historical and cultural city, an important industrial, scientific, and educational base, and a key transportation hub. There are many schools in Wuhan, with nearly a thousand of all kinds. The number of students is ~2.2 million, accounting for nearly one-fifth of the resident population; college or university students account for ~60% of the total student population. The geographical location of these colleges is relatively concentrated, and the population density is relatively high, making it prone to tuberculosis cluster epidemic.

Objective

This study analyzed the epidemiological characteristics and influencing factors of tuberculosis aggregation in schools in Wuhan, China, during 2017-2022 to provide the basis for the scientific development of tuberculosis prevention and control strategies and measures in schools.

Methods

This study adopted the methods of descriptive epidemiology to analyze the epidemic characteristics of tuberculosis aggregation in schools in Wuhan from January 2017 to December 2022, collecting the relevant data on tuberculosis prevention and control in all kinds of schools in the city using Questionnaire Star, an application of the China network questionnaire survey, and analyze the influencing factors of tuberculosis aggregation by using multifactor logistic regression analysis.

Results

From 2017 to 2022, 54 outbreaks of pulmonary tuberculosis aggregation in schools were reported in Wuhan, which involved 37 different schools, including 32 colleges or universities and five senior high schools; 176 cases were reported, among which 73 were positive for pathogens and 18 were rifampicin or izoniazid resistant. The median duration of a single cluster epidemic was 46 (26,368) days. Universities were more prone to cluster outbreaks than middle schools (χ2 = 105.160, P = 0.001), and the incidence rate among male students was higher than that of female students in cluster epidemics (χ2 = 12.970, P = 0.001). The multivariate logistic regression analysis results showed that boarding in school (OR = 7.60) is the risk factor for a tuberculosis cluster epidemic in schools. The small number of students (OR = 0.50), the location of the school in the city (OR = 0.60), carry out physical examinations for freshmen (OR = 0.44), carry out illness absence and cause tracking (OR = 0.05), dormitories and classrooms are regularly ventilated with open windows (OR = 0.16), strict implement the management of sick student's suspension from school (OR = 0.36), and seeking timely medical consultation (OR = 0.32) were the protective factors for a tuberculosis cluster epidemic in schools.

Conclusion

We successfully identified the epidemiological characteristics and influencing factors of tuberculosis aggregation in schools in Wuhan. The results revealed the influence and status of various factors and indicated ways for schools to improve their TB prevention and control measures in their daily activities. These measures can effectively help curb the cluster epidemic of tuberculosis in schools.

The role of Xpert MTB/RIF using bronchoalveolar lavage fluid in active screening: insights from a tuberculosis outbreak in a junior school in eastern China

Background

Tuberculosis (TB) outbreaks in schools present a public health challenge. In order to effectively control the spread of transmission, timely screening, accurate diagnosis and comprehensive epidemiological investigations are essential.

Methods

In July 2021, a TB outbreak occurred in a junior high school in Y City, Zhejiang Province. Students and faculty were screened for TB by symptom screening, chest radiography, and tuberculin skin test during four rounds of contact screenings. For sputum smear-negative and sputum-scarce patients, bronchoscopy was used to collect BAL samples for Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF). Whole-genome sequencing and bioinformatics analysis were performed on isolates to identify the strains of MTB isolates and predict drug resistance.

Results

Between July 2021 and November 2021, a total of 1,257 students and faculty were screened for TB during screenings. A total of 15 students (1.2% of persons screened) aged 15 years were diagnosed with TB. Eighty percent (12/15) of the cases were laboratory-confirmed (10/12 [83%] Xpert MTB/RIF-positive, 2/12 [17%] culture-positive). Most cases (12/15 [80%]) were in students from Class 2. All cases were asymptomatic except for the index case who had symptoms for more than two months. Seven MTB isolates were collected and belonged to lineage 2.

Conclusion

Our findings demonstrated the potential of Xpert MTB/RIF using BAL as a screening tool in school TB outbreaks for sputum smear-negative and sputum-sparse suspects, which may not only rapidly improves diagnostic accuracy, but also facilitates epidemiological investigations and homology analysis.

Spatial-temporal analysis of pulmonary tuberculosis among students in the Zhejiang Province of China from 2007-2020

Background

Pulmonary tuberculosis (PTB) is a serious chronic communicable disease that causes a significant disease burden in China; however, few studies have described its spatial epidemiological features in students.

Methods

Data of all notified PTB cases from 2007 to 2020 in the student population were collected in the Zhejiang Province, China using the available TB Management Information System. Analyses including time trend, spatial autocorrelation, and spatial-temporal analysis were performed to identify temporal trends, hotspots, and clustering, respectively.

Results

A total of 17,500 PTB cases were identified among students in the Zhejiang Province during the study period, accounting for 3.75% of all notified PTB cases. The health-seeking delay rate was 45.32%. There was a decreasing trend in PTB notifications throughout the period; clustering of cases was seen in the western area of Zhejiang Province. Additionally, one most likely cluster along with three secondary clusters were identified by spatial-temporal analysis.

Conclusion

Although was a downward trend in PTB notifications among students during the time period, an upward trend was seen in bacteriologically confirmed cases since 2017. The risk of PTB was higher among senior high school and above than of junior high school. The western area of Zhejiang Province was the highest PTB risk settings for students, and more comprehensive interventions should be strengthened such as admission screening and routine health monitoring to improve early identification of PTB.

The effect of BCG vaccination and risk factors for latent tuberculosis infection among college freshmen in China

OBJECTIVES

In this study, we aimed to verify whether Bacillus Calmette-Guérin (BCG) can protect first-year college students against Mycobacterium tuberculosis (MTB) infection by the recombinant fusion protein ESAT6-CFP10 skin test (ECST) or the tuberculin skin test (TST).

METHODS

We conducted a cross-sectional study to assess risk factors for latent tuberculosis infection (LTBI). Vaccine effectiveness of BCG against LTBI, measured by ECST and TST separately, was assessed using multivariable logistic regression.

RESULTS

A total of 7351 college freshmen accepted ECST, whereas 7228 accepted TST. A total of 263 (3.58%) tested positive with ECST and 581 (8.04%) tested positive with TST. BCG was significantly associated with LTBI (ECST: adjusted odds ratio (aOR) = 0.26; 95% CI 0.09 to 0.73; TST: aOR = 0.25; 95% CI 0.13 to 0.49). The BCG protective effect on freshmen living in rural areas (ECST: aOR = 0.16; 95% CI 0.04 to 0.55; TST: aOR = 0.12; 95% CI 0.04 to 0.33) is better than that of freshmen living in cities (ECST: aOR = 0.53; 95% CI 0.07 to 4.03; TST: aOR = 0.44; 95% CI 0.17 to 1.16).

CONCLUSIONS

Protection against LTBI was strongly associated with BCG vaccination. A novel skin test (ECST) may underestimate the protective effects of BCG in college freshmen. BCG has better protection in areas with a slightly higher incidence of LTBI.

High rate of transmission in a pulmonary tuberculosis outbreak in a junior high school in China, 2020

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School tuberculosis outbreaks are common in China

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Students with PPD ≥ 15 mm are recommended to have prophylactic treatment

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More attention should be paid to students with PPD ≥ 10 mm and < 15 mm in school TB outbreaks

Background

School tuberculosis outbreaks are common in China. This study aimed to introduce a new screening process to help control outbreaks.

Methods

An epidemiological investigation into a school-based tuberculosis outbreak was conducted in order to identify the origin of the infection, and how it was transmitted.

Results

In total, 10 confirmed active tuberculosis cases were diagnosed among student contacts in the index case's class, giving an incidence rate of 19.2% (10/52). Three were found through a proactive visit and seven through screening. Of the nine secondary cases, two had purified protein derivation of tuberculin (PPD) ≥ 15 mm or blister (confirmed by computed tomography (CT) scan before preventive therapy), five had TST ≥ 10 mm and < 15 mm (two with abnormal chest radiography scan and three with positive T-SPOT tests, confirmed by CT) and two with PPD ≥ 5 mm and < 10 mm (confirmed by CT scan through proactive visit).

Conclusion

Further to our results based on this school outbreak, a new screening process is recommended that involves conducting interferon gamma release assays on those students with PPD ≥ 5 mm and < 15 mm if there are three or more active tuberculosis patients in the class with an epidemiological link. Furthermore, a CT scan is recommended for students who have had a recent tuberculosis infection before they have preventive therapy.

Tuberculosis Outbreak in an Educational Institution in Henan Province, China

On June 17, 2018, a case of pulmonary tuberculosis (TB) was reported among students at a senior high school in Luoning, China. The outbreak encompassed a total of 23 cases along with TB screening in the whole school by means of PPD and chest X-ray. By the end of September 2018, the entire 9 cases cultured positive had epidemiological association. All of the 9 Mycobacterium tuberculosis (Mtb) isolates available were sensitive to all drugs tested and had similar spoligotyping and 15 loci mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) profile. Whole-genome sequencing (WGS) of the Mtb isolates revealed 20 variable nucleotide positions within 8 cases, indicating a clonal outbreak. The index case, which was first identified and diagnosed, is separated from the cluster by a minimum number of 95 distinct SNPs. Minimum distance spanning tree (MST) indicted that the 8 cases were indeed part of a single transmission chain. It was concluded that this is an epidemic situation of TB outbreak exposed by the aggrieved index case at school, which was caused by the veiled infectious case wherein a student was suffering from TB and attending school simultaneously.

Reporting practices for genomic epidemiology of tuberculosis: a systematic review of the literature using STROME-ID guidelines as a benchmark

BACKGROUND

Pathogen genomics have become increasingly important in infectious disease epidemiology and public health. The Strengthening the Reporting of Molecular Epidemiology for Infectious Diseases (STROME-ID) guidelines were developed to outline a minimum set of criteria that should be reported in genomic epidemiology studies to facilitate assessment of study quality. We evaluate such reporting practices, using tuberculosis as an example.

METHODS

For this systematic review, we initially searched MEDLINE, Embase Classic, and Embase on May 3, 2017, using the search terms "tuberculosis" and "genom* sequencing". We updated this initial search on April 23, 2019, and also included a search of bioRxiv at this time. We included studies in English, French, or Spanish that recruited patients with microbiologically confirmed tuberculosis and used whole genome sequencing for typing of strains. Non-human studies, conference abstracts, and literature reviews were excluded. For each included study, the number and proportion of fulfilled STROME-ID criteria were recorded by two reviewers. A comparison of the mean proportion of fulfilled STROME-ID criteria before and after publication of the STROME-ID guidelines (in 2014) was done using a two-tailed t test. Quasi-Poisson regression and tobit regression were used to examine associations between study characteristics and the number and proportion of fulfilled STROME-ID criteria. This study was registered with PROSPERO, CRD42017064395.

FINDINGS

976 titles and abstracts were identified by our primary search, with an additional 16 studies identified in bioRxiv. 114 full texts (published between 2009 and 2019) were eligible for inclusion. The mean proportion of STROME-ID criteria fulfilled was 50% (SD 12; range 16-75). The proportion of criteria fulfilled was similar before and after STROME-ID publication (51% [SD 11] vs 46% [14], p=0·26). The number of criteria reported (among those applicable to all studies) was not associated with impact factor, h-index, country of affiliation of senior author, or sample size of isolates. Similarly, the proportion of criteria fulfilled was not associated with these characteristics, with the exception of a sample size of isolates of 277 or more (the highest quartile). In terms of reproducibility, 100 (88%) studies reported which bioinformatic tools were used, but only 33 (33%) reported corresponding version numbers. Sequencing data were available for 86 (75%) studies.

INTERPRETATION

The reporting of STROME-ID criteria in genomic epidemiology studies of tuberculosis between 2009 and 2019 was low, with implications for assessment of study quality. The considerable proportion of studies without bioinformatics version numbers or sequencing data available highlights a key concern for reproducibility.

Whole-genome sequencing and epidemiological analysis of a tuberculosis outbreak in a high school of southern China

Tuberculosis (TB) is a serious global public health threat, and school-clustered outbreaks are common. Here, we report a TB outbreak in a high school in southern China, which was confirmed and characterized by traditional epidemiological methods and whole-genome sequencing (WGS) of Mycobacterium tuberculosis isolates. All students and faculty (n = 287) were screened by chest X-ray for active TB. TB was diagnosed in 28 patients, according to laboratory confirmation (n = 11) of Mycobacterium tuberculosis, sputum/bronchoalveolar fluid culture, smear, or TB-Xpert. Clinically diagnosed TB cases (n = 17) were further defined by the interferon-γ releasing assay or clinical and radiological findings. Twenty-five of the affected individuals were 12th grade students aged 16 to 19 years; among them, 24 patients were male and 21 had visited the internet café near the school. WGS and phylogenetics analysis confirmed that the outbreak was mainly caused by a super transmission strain of lineage 4.2, which was susceptible to all tested antibiotics. After a treatment regimen of 9 to12 months, all 28 patients were cured. This study highlights the key factors contributing to school-clustered TB outbreaks mainly derived from a single super transmission strain, along with effective interventional measures to prevent a larger scale outbreak.

The epidemiology of pulmonary tuberculosis in children in Mainland China, 2009-2015

OBJECTIVE

To describe the incidence and epidemiological characteristics of child pulmonary tuberculosis (PTB) notified to the Chinese Center for Disease Control and Prevention (CDC) Tuberculosis Information Management System (TBIMS) from 2009 to 2015.

STUDY DESIGN

A database of child PTB for 31 provinces in mainland China over 7 years was retrospectively analysed. The spatiotemporal distribution of child PTB was described.

RESULTS

In total, 35,710 child PTB cases were notified to the TBIMS, representing only 0.60% of all 5,991,593 PTB case notifications. The average annual notified incidence of child PTB was 2.44/ per 100,000 children (95% CI: 1.77-3.10) and decreased by 52.53% in all age groups during the study period. Tibet had the highest incidence (15.95/ per 100,000 children), followed by Guizhou and Xinjiang. However, the case numbers were the most in Guizhou. The 0-1 year and 12-14 years of age groups exhibited the most cases. The positive rates of sputum smears, bacteriology and chest X-rays abnormality were 21.5%, 21.7% and 98.1%, respectively, which were lower than those 15 years of age and older (all p-values<0.0001).

CONCLUSION

The notified incidence of child PTB in mainland China decreased substantially over 7 years. Future prevention and control of PTB in children should focus on the 0-1 and 12-14 years of age groups, and Tibet and Guizhou provinces. However, the notified incidence is still low, relative to adults, suggesting substantial under-reporting. Thus, more effective care seeking, identification and registration of children with TB are crucial.

A tuberculosis school outbreak in China, 2018: reaching an often overlooked adolescent population

Adolescents have been largely neglected from tuberculosis control efforts. In low- to medium burden settings much of the tuberculosis burden in this age group occurs from school outbreaks. We report on a large tuberculosis outbreak in adolescents from a boarding high school in Jiangsu Province, China. From March to June 2018, a tuberculosis outbreak occurred in a boarding high school. We conducted an outbreak investigation involving clinical diagnostic tests and molecular analysis to determine the outbreak origin. Cases were detected through symptom screening, tuberculin skin testing (TST), chest radiography, sputum smear, solid sputum culture and GeneXpert MTB/RIF. Mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) genotyping and spoligotyping methods were performed on Mycobacterium tuberculosis (M. tuberculosis) isolates to identify the outbreak origin. A total of 845 students and 131 teachers/staff attended a TST screening for tuberculosis infection. The prevalence of elevated tuberculin reactions at ≥5, ≥10 and ≥15 mm was 12.19% (119/976), 6.35% (62/976) and 3.28% (32/976), respectively. Radiographic abnormalities were present in 5.73% (56 of 976) individuals, 40 students and 16 teachers/staff. Of these, 12 students were diagnosed with confirmed tuberculosis. In total, 14 students (two index cases and 12 confirmed cases) were diagnosed and reported in the tuberculosis outbreak, an attack rate of 1.7% (14/847) among students (two index cases and 845 screened students). Results from MIRU-VNTR typing and spoligotyping analyses demonstrated that three M. tuberculosis strains belong to the Beijing family with corresponding MIRU-VNTR alleles. This school-based tuberculosis outbreak among adolescents demonstrates that transmission among individuals in this age group is common and must be prioritised. It suggests that identifying and timely diagnosis of smear-positive cases, especially in the early phase of outbreaks, is the key to preventing further spread among close contacts.

Spatiotemporal Distribution of Tuberculosis during Urbanization in the New Urban Area of Nanchang City, China, 2010-2018

Background: Urbanization will play a key role in ending the tuberculosis (TB) epidemic by 2030, but understanding the relationship between urbanization and the health threats posed by TB is incomplete. Therefore, this study aimed to explore the spatiotemporal distribution of TB at the township level during urbanization in the new urban area of Nanchang. Methods: Seasonal-trend decomposition of time series analysis was used to explore the seasonal distribution and trend analysis. Global and local spatial autocorrelation statistics, and space–time scan statistics were performed to detect the spatiotemporal clusters of TB cases in the new urban area of Nanchang from 2010 to 2018. Results: A total of 3245 TB cases were reported in the study area from 2010 to 2018. Of all the TB cases, 68% occurred in individuals older than 40 years old, 73.2% were male cases, and 56.6% were farmers. The primary seasonal peak was in late spring (April), and a smaller peak was in early autumn (September). The results of local indicators of spatial association showed that Jiaoqiao town and Changleng town might be “High–High” clusters. The most likely spatiotemporal cluster was located in the southwest of the study area in 2010, which included five towns, and then shifted to the northeast gradually. Across 2010 to 2018, nine spatiotemporal clusters were identified. The most likely cluster was located at the northeast of the study area. The center of this area was in Nanji town with a circle radius of 43.74 kilometers. Conclusions: The spatial clusters of TB incidence shifted to the rural region and the fringe of the new urban area of Nanchang. Targeted management strategies for urban migrants in the process of urbanization should be strengthened.

Whole-Genome Sequencing as Tool for Investigating International Tuberculosis Outbreaks: A Systematic Review

Background: Whole-genome sequencing (WGS) can support the investigation of tuberculosis (TB) outbreaks. The technique has been applied to estimate the timing and directionality of transmission and to exclude cases from an investigation. This review assesses how WGS was applied in international outbreak investigations and discusses the advantages and challenges of the application of WGS.

Methods: Databases were searched for reports on international TB outbreak investigations. Information was extracted on: Why was WGS applied?; How was WGS applied?; Organizational issues; WGS methodology; What was learned/what were the implications of the WGS investigation?; and challenges and lessons learned.

Results: Three studies reporting on international outbreak investigations were identified. Retrospective WGS sequencing was performed in all studies and prospective typing in two to study TB transmission. In one study, WGS data were produced centrally (i.e., in one laboratory) and analysis was done centrally. In two studies, WGS data production was done in a decentralized manner, and analysis was centralized in one laboratory. Three groups of professionals were involved in the international outbreak investigation: public health authorities, laboratory experts, and clinicians. The reported WGS methodology applied differed between the studies in some aspects, e.g., sequencing platform; quality measures, percentage of the reference genome covered, and the mean genomic coverage; analysis, use of a reference genome or de novo assembly; and software used for alignment and analysis. In all three studies, in-house scripts were used for variance calling, and the single nucleotide polymorphism (SNP) approach was used for analysis. All outbreak investigation reports stated that WGS refuted suspected transmission events and provided supporting evidence for epidemiological data. Several challenges were reported of which most were not related to WGS. The only challenge related to WGS was the timeframe of getting WGS data if WGS is not routinely performed.

Conclusions: WGS was considered a useful addition in international TB outbreak investigations. Further standardization of the WGS methodology and good structures for international collaboration and coordination are needed to take full advantage of this new technology. Whether the use of WGS results in earlier detection of cases and thus limits transmission still needs to be determined.

Diagnostic delay as main contributing factor to a large outbreak of tuberculosis in a university

OBJECTIVE

To describe the epidemiological characteristics of a large tuberculosis outbreak in the university environment and the main risk factors associated with it.

METHOD

A descriptive analysis of the data collected from sick individuals and their contacts was made. For the contact tracing, the guidelines established in the Tuberculosis Programme of the Autonomous Community of the Basque Country were followed. Six of the outbreak strains were sent to the National Centre of Microbiology for molecular typing.

RESULTS

The total number of cases of the outbreak was 11. The rate of tuberculosis infection in the classroom of the index case, including the sick individuals, was 88.1% (59 infected and only 8 uninfected). The diagnostic delay of the index case was 260 days, and in the other 8 symptomatic cases it ranged between 10 and 70 days. The pattern obtained by the 2genotyping techniques was identical in the 6 strains studied.

CONCLUSIONS

The long diagnostic delay of the authentic index case, which was diagnosed in the contact tracing, and the poor ventilation conditions of the classroom, determined the high number of secondary cases associated with this outbreak.

Tuberculosis Transmission in Households and Classrooms of Adolescent Cases Compared to the Community in China

The aim of this paper is to evaluate the link between the history of exposure to tuberculosis (TB) in the household and diagnosed TB cases at school, and to compare the detection rate of active TB among household contacts and classroom contacts of adolescent TB cases with the rates among contacts of healthy controls. From November 2016 to December 2017, a prospective matched case-control study was conducted using passively identified index adolescent student cases from the TB surveillance system and healthy controls (matched by county, school type, sex, age and ethnicity). Contacts in households and classrooms of index cases and of controls were investigated. Matched tabulation of 117 case-control pairs revealed exposure to TB in the household as a strong risk factor (odds ratio (OR) = 21.0, 95% confidence interval (CI): 3.4, 868.6). Forty-five (case detection rate 0.69%) and two (case detection rate 0.03%) new active TB cases were detected among 6512 and 6480 classroom contacts of the index cases and controls, respectively. Having an index case in the classroom significantly increased the risk of classmates contracting active TB (OR = 22.5, 95% CI: 5.9, 191.4). Our findings suggested that previous exposure to TB in the household could lead a child to catch TB at school, then spread TB to classmates.

Spatial and temporal clustering analysis of tuberculosis in the mainland of China at the prefecture level, 2005-2015

Background

Tuberculosis (TB) is still one of the most serious infectious diseases in the mainland of China. So it was urgent for the formulation of more effective measures to prevent and control it.

Methods

The data of reported TB cases in 340 prefectures from the mainland of China were extracted from the China Information System for Disease Control and Prevention (CISDCP) during January 2005 to December 2015. The Kulldorff’s retrospective space-time scan statistics was used to identify the temporal, spatial and spatio-temporal clusters of reported TB in the mainland of China by using the discrete Poisson probability model. Spatio-temporal clusters of sputum smear-positive (SS+) reported TB and sputum smear-negative (SS-) reported TB were also detected at the prefecture level.

Results

A total of 10 200 528 reported TB cases were collected from 2005 to 2015 in 340 prefectures, including 5 283 983 SS- TB cases and 4 631 734 SS + TB cases with specific sputum smear results, 284 811 cases without sputum smear test. Significantly TB clustering patterns in spatial, temporal and spatio-temporal were observed in this research. Results of the Kulldorff’s scan found twelve significant space-time clusters of reported TB. The most likely spatio-temporal cluster (RR = 3.27, P <  0.001) was mainly located in Xinjiang Uygur Autonomous Region of western China, covering five prefectures and clustering in the time frame from September 2012 to November 2015. The spatio-temporal clustering results of SS+ TB and SS- TB also showed the most likely clusters distributed in the western China. However, the clustering time of SS+ TB was concentrated before 2010 while SS- TB was mainly concentrated after 2010.

Conclusions

This study identified the time and region of TB, SS+ TB and SS- TB clustered easily in 340 prefectures in the mainland of China, which is helpful in prioritizing resource assignment in high-risk periods and high-risk areas, and to formulate powerful strategy to prevention and control TB.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0490-8) contains supplementary material, which is available to authorized users.

Implications of a school outbreak of multidrug-resistant tuberculosis in Northern China

In this study, we identified a multidrug-resistant tuberculosis (MDR-TB) outbreak in a high school in northern China. The aim of this work was to describe TB transmission, drug resistance and treatment outcomes for this patient cluster. In January 2017, pulmonary TB was identified in a 17-year-old boy in northern China. Subsequently, a total of 11 TB cases were identified during 6-month follow-up of attendees of the same school. Of five students with latent TB infection (LTBI) receiving isoniazid preventive therapy (IPT), two pulmonary TB cases (40.0%) emerged in March and April, for an active case rate not significantly different from that of the non-IPT group (4/16, 25.0%, P = 0.598). All TB patients were first treated with a standardised first-line treatment regimen administered by the local TB hospital, with 11 of 12 active TB patients exhibiting poor treatment outcomes. Further data demonstrated that all nine patient isolates collected during this outbreak were MDR-TB and shared a common genotypic profile. In conclusion, our data demonstrate that diagnostic delay for the index MDR-TB case of this outbreak played a primary role in transmission of MDR-TB infection within a school setting. Importantly, IPT failed to prevent progression of MDR-TB from LTBI to active TB.

Recent transmission of Mycobacterium tuberculosis in China: the implication of molecular epidemiology for tuberculosis control

Tuberculosis (TB) has remained an ongoing concern in China. The national scale-up of the Directly Observed Treatment, Short Course (DOTS) program has accelerated the fight against TB in China. Nevertheless, many challenges still remain, including the spread of drug-resistant strains, high disease burden in rural areas, and enormous rural-to-urban migrations. Whether incident active TB represents recent transmission or endogenous reactivation has helped to prioritize the strategies for TB control. Evidence from molecular epidemiology studies has delineated the recent transmission of Mycobacterium tuberculosis (M. tuberculosis) strains in many settings. However, the transmission patterns of TB in most areas of China are still not clear. Studies carried out to date could not capture the real burden of recent transmission of the disease in China because of the retrospective study design, incomplete sampling, and use of low-resolution genotyping methods. We reviewed the implementations of molecular epidemiology of TB in China, the estimated disease burden due to recent transmission of M. tuberculosis strains, the primary transmission of drug-resistant TB, and the evaluation of a feasible genotyping method of M. tuberculosis strains in circulation.

Tuberculosis among Jimma University Undergraduate Students: First Insight about the Burden of Tuberculosis in Ethiopia Universities-Cross-Sectional Study

Background

Ethiopian universities are facilities where students live in relative overcrowding condition. This might favor the chance of tuberculosis transmission among students. This study was done to determine the magnitude and associated factors of tuberculosis among Jimma University students.

Methods

A cross-sectional study was done from February 2015 to July 2015. Hundred twenty-nine consented participants were interviewed using structured questionnaire. Biological specimens were collected and cultured on Mycobacterium Growth Indicator Tube. Mycobacterium tuberculosis complex verification was done by SD BIOLINE TB Ag MPT64 Rapid test. Frequency distribution, logistic regression, and independent sample t-test were used to analyze the data using SPSS Version 20.

Result

Magnitude of all forms of tuberculosis among Jimma University undergraduate students was 209.1 per 100000-student population. Contact history [AOR: 4.76, 95% CI (1.31–17.31)], smoking [AOR: 6.67, 95% CI (1.51–29.44)], khat chewing [AOR: 5.56, 95% CI (1.66–18.69)], and low body mass index [AOR: 5.37, 95% CI (1.46–19.78)] were determinants of tuberculosis.

Conclusion

The magnitude of tuberculosis among Jimma University undergraduate students is high. TB is associated with previous tuberculosis patient contact and behavioral factors. Hence, students with these risk factors should be given enough attention for the control of TB in Jimma University.

ESMPE: A combined strategy for school tuberculosis prevention and control proposed by Dalian, China

BACKGROUND

Although China has paid more attention on the prevention and control of tuberculosis (TB) in schools, several unsolved questions in this field still threaten the progress of TB control. Therefore, there is an urgent need to develop a systematic and practical strategy for Chinese school TB prevention and control system. In this study, we aimed to assess the feasibility of a combined strategy named ESMPE (examination, screening, monitoring, prevention and education) that adhere to the basic principles of Chinese schools TB control strategy.

METHODS

The ESMPE strategy included five sections, namely TB screening during physical examination for the school freshmen entrances, screening of close contacts, monitoring of high-risk schools, preventive treatment and TB education. The effectiveness of ESMPE strategy was evaluated from 2011 to 2016. The original data were provided by the Dalian Tuberculosis Hospital. Descriptive analysis and nonparametric tests were used for comparing statistical differences of results between different years.

RESULTS

The detection rate of active pulmonary TB in school freshmen was decreased from 2011 to 2016 (χ2 = 41.941, P = 6.0551E-8). 97.22% (17,043/17,530) of close contacts experienced close contacts screening, and the secondary attack rate (SAR) of TB in schools fell by 146.35/105 from 2011 to 2012, and finally reduced to 85.57/105 in 2016. There was a significant correlation between SAR of student TB and the rate of screened close contacts (r = -0.924, P = 0.009). TB incidence of five monitored schools had a substantial decline after receiving monitoring, and this declining trend continued in 2016. Due to the TB education and advanced screening methods, the mean of diagnostic delay time in students with TB was shortened (15.71 days), while still fewer latent TB infection students received preventive treatment (30.38%).

CONCLUSIONS

The ESMPE strategy has shown a favorable effect on TB prevention and control in Dalian schools. More systematic evidence is needed on the effect of this strategy in reducing the incidence of TB in schools from other settings prior to its further scaling-up in China.

Impact of HIV co-infection on the evolution and transmission of multidrug-resistant tuberculosis

The tuberculosis (TB) epidemic is fueled by a parallel Human Immunodeficiency Virus (HIV) epidemic, but it remains unclear to what extent the HIV epidemic has been a driver for drug resistance in Mycobacterium tuberculosis (Mtb). Here we assess the impact of HIV co-infection on the emergence of resistance and transmission of Mtb in the largest outbreak of multidrug-resistant TB in South America to date. By combining Bayesian evolutionary analyses and the reconstruction of transmission networks utilizing a new model optimized for TB, we find that HIV co-infection does not significantly affect the transmissibility or the mutation rate of Mtb within patients and was not associated with increased emergence of resistance within patients. Our results indicate that the HIV epidemic serves as an amplifier of TB outbreaks by providing a reservoir of susceptible hosts, but that HIV co-infection is not a direct driver for the emergence and transmission of resistant strains.