Incidence Of Tuberculosis Disease Research Articles

The Risk of Tuberculosis Disease Among Persons With Diabetes Mellitus: A Prospective Cohort Study

Evidence suggests a causal link between diabetes mellitus and tuberculosis risk. However, to date, few studies have used a prospective design to estimate the impact of diabetes on tuberculosis in a general population. In this study, we prospectively investigated the risk of tuberculosis among persons with diabetes stratified by severity. A cohort study was performed that involved 17,715 Taiwanese persons on whom baseline data were collected during Taiwan's 2001 National Health Interview Survey. Participants' subsequent medical care until December 2004 was captured from the National Health Insurance database. The diagnosis and severity of diabetes were established using self-report, International Classification of Diseases, Ninth Revision, Clinical Modification codes, and pharmacy records; incident tuberculosis disease was identified using these codes and pharmacy records. Covariates were obtained through in-person interviews. We used Cox proportional hazards regression analyses to measure the association between tuberculosis and both diabetes and diabetes severity. Diabetes in general and treated diabetes were significantly associated with tuberculosis (adjusted hazard ratio, 2.09 [95% confidence interval {CI}, 1.10-3.95] and 2.60 [95% CI, 1.34-5.03], respectively). Compared with persons without treated diabetes, participants' risk of tuberculosis increased as the number of complications of diabetes mellitus increased (P = .0016), with >3-fold risk among those with ≥ 2 diabetes-related complications (odds ratio, 3.45; 95% CI, 1.59-7.50). Similarly, the risk increased among those with higher Diabetes Complications Severity Index scores (P = .0002). The risk of developing tuberculosis increased among those with increasing diabetes severity.

Risky behaviour and psychosocial correlates in adolescents – is there a link with tuberculosis?

Reasons for the increase in incidence of tuberculosis (TB) in late adolescence are poorly understood. One hypothesis is that psychological and behavioural variables associated with adolescence may increase risk of developing TB. The study aimed to determine whether psychosocial and behavioural variables affect incidence of TB disease in adolescents. A case-control study design was used in adolescents who were participants in a TB epidemiological study. Cases were adolescents diagnosed with TB disease. Approximately half of the controls had no TB disease but a positive TST indicative of latent TB. Half had neither TB disease nor latent TB. A self-administered questionnaire was completed by participants. The questionnaire consisted of a combination of standardised psychosocial instruments. Of 292 participants, 62 were cases, 112 had latent TB and 118 neither TB disease nor latent TB. There were no significant differences in instrument scores between cases and controls. There was a trend for certain adverse life events to be more common in the TB-disease group. In adolescents, a trend for association between TB incidence and psychosocial and behavioural variables was not statistically significant. Given the trend, research with larger samples, and more comprehensive assessment of the relationship between stressors and TB, is warranted.

Clinical characteristics and outcomes of Mycobacterium tuberculosis disease in adult patients with hematological malignancies

BackgroundDiseases caused by Mycobacterium tuberculosis (TB) among adult patients with hematological malignancies have rarely been investigated.MethodsAdult patients with hematological malignancies at National Taiwan University Hospital between 1996 and 2009 were retrospectively reviewed. Patients with positive serology for HIV were excluded. TB disease is diagnosed by positive culture(s) in the presence of compatible symptoms and signs. The demographics, laboratory and, microbiological features, were analyzed in the context of clinical outcomes.ResultsFifty-three of 2984 patients (1.78%) were diagnosed with TB disease. The estimated incidence was 120 per 100,000 adult patients with hematological malignancies. Patients with acute myeloid leukemia had a significantly higher incidence of TB disease than other subtypes of hematological malignancies (2.87% vs. 1.21%, p = 0.002, odds ratio, 2.40; 95% confidence interval, 1.39-4.41). Thirty-eight patients (72%) with non-disseminated pulmonary TB disease presented typically with mediastinal lymphadenopathy (53%), pleural effusion (47%) and fibrocalcific lesions (43%) on chest imaging. The 15 (28%) patients with extra-pulmonary disease had lower rates of defervescence within 72 h of empirical antimicrobial therapy (13% vs 45%, p = 0.03) and a higher 30-day in-hospital mortality (20% vs. 0%, p = 0.004) compared to those with disease confined to the lungs.ConclusionsTB disease is not uncommon among patients with hematological malignancies in Taiwan. Patients who received a diagnosis of extra-pulmonary TB suffered higher mortality than those with pulmonary TB alone. Clinicians should consider TB in the differential diagnoses of prolonged fever in patients with hematological malignancies, particularly in regions of high endemicity.

Prevalence of Latent Infection with Mycobacterium Tuberculosis in Mazowieckie Province Using Interferon Gamma Release Assay after Stimulation with Specific Antigens ESAT-6 and CFP-10

Introduction: Over 8000 cases of tuberculosis (TB) are diagnosed annually in Poland. People infected with Mycobacterium tuberculosis (MTB) have a risk of active disease of around 10% during their whole life, and the risk is highest in the first two years after infection. Recognizing infection before TB disease development enables prophylaxis against its activation and ceases transmission of infection. Knowledge about the proportion of infected people in the population is crucial to predict the number of new cases of active disease. Materials and methods: The prevalence of latent TB infection (LTBI) was tested in 700 healthy adult inhabitants of the Mazowieckie province in different age groups, using both tuberculin skin test (TST) and interferon gamma release assay (IGRA). Commercial test QuantiFERON®-TB-Gold In Tube (QFT) was used. All participants were mandatorily BCG vaccinated according to the Polish vaccination schedule. Results: Twenty-three per cent of participants tested positively for QFT, which was significantly less than for TST (50.3%). The prevalence of positive QFT results increased with age, as well as the incidence of TB in Poland. Positive QFT was most frequent in the oldest age group (48.8%) and rarest in the youngest (7.1%). Conversely, positive TST occurred more often in younger participants (45%), who rarely suffer from TB. Among people over 60, with the highest TB incidence rate, only 33.8% tested positively with TST. Concordance between both tests was low, with a kappa value of 0.198. The prevalence of LTBI defined as positive QFT among health care workers (HCW) was significantly higher than among other participants (32.2% v. 20.4%, p < 0.01). Conclusions: LTBI was diagnosed in 23.3% of the tested population of the Mazowieckie province. QFT is a better tool for diagnosing LTBI as it shows a positive correlation with age (as the incidence of TB disease does). Concordance between both tests is low. The prevalence of LTBI in HCW is higher than in other participants.

Tuberculosis in household contacts of multidrug-resistant tuberculosis patients

The burden of tuberculosis (TB) disease among household contacts of multidrug-resistant TB (MDR-TB) patients is poorly understood and might represent a target for transmission-interrupting interventions. This retrospective cohort study, conducted in Lima, Peru, from June to September 2008, estimated the incidence of TB disease among household contacts of MDR-TB patients in 358 households. Of 2112 household contacts in 80 households (22% of households), 108 (5%) developed TB disease during the study, giving an incidence rate of 2360 per 100 000 contact follow-up years for each of the first 3 years after exposure. Drug susceptibility tests (DST) were available for 50 diseased contacts, of whom 36 (80%) had MDR-TB. Forty-two pairs of index-contact DSTs were available, among which the contact had an identical or less resistant phenotype than the index case in 27 pairs. Multivariate Cox regression demonstrated that male contacts (hazard ratio [HR] 2.8, P < 0.05), with previous TB disease (HR 20.7, P < 0.001) and with associated (non-human immunodeficiency virus) comorbidities (HR 11.2, P < 0.001) were more likely to develop TB. The high percentage of diseased household contacts highlights an opportunity for household-level interventions to prevent transmission, whether or not these cases were all attributable to the index case.

The Tuberculin Skin Test versus QuantiFERON TB Gold® in Predicting Tuberculosis Disease in an Adolescent Cohort Study in South Africa

SettingThis study was conducted in a high tuberculosis (TB) burden area in Worcester, South Africa, with a notified all TB incidence rate of 1,400/100,000.Main ObjectiveTo compare the predictive value of a baseline tuberculin skin test (TST) with that of the QuantiFERON TB Gold (In-tube) assay (QFT) for subsequent microbiologically confirmed TB disease among adolescents.MethodsAdolescents aged 12–18 years were recruited from high schools in the study area. At baseline, blood was drawn for QFT and a TST administered. Participants were followed up for up to 3.8 years for incident TB disease (median 2.4 years).ResultsAfter exclusions, 5244 (82.4%) of 6,363 adolescents enrolled, were analysed. The TB incidence rate was 0.60 cases per 100 person years (pyrs) (95% CI 0.43–0.82) for baseline TST positive (≥5 mm) participants and 0.64 cases per 100 pyrs (95% CI 0.45–0.87) for baseline QFT positive participants. TB incidence rates were 0.22 per 100 pyrs (0.11–0.39) and 0.22 per 100 pyrs (0.12–0.38) among those with a negative baseline TST and QFT respectively. Sensitivity for incident TB disease was 76.9% for TST and 75.0% for QFT (p = 0.81). Positive predictive value was 1.4% for TST and 1.5% for QFT.ConclusionPositive TST and QFT tests were moderately sensitive predictors of progression to microbiologically confirmed TB disease. There was no significant difference in the predictive ability of these tests for TB disease amongst adolescents in this high burden setting. Therefore, these findings do not support use of QFT in preference to TST to predict the risk of TB disease in this study population.

Tuberculosis Incidence in Prisons: A Systematic Review

Transmission of tuberculosis (TB) in prisons has been reported worldwide to be much higher than that reported for the corresponding general population. A systematic review has been performed to assess the risk of incident latent tuberculosis infection (LTBI) and TB disease in prisons, as compared to the incidence in the corresponding local general population, and to estimate the fraction of TB in the general population attributable (PAF%) to transmission within prisons. Primary peer-reviewed studies have been searched to assess the incidence of LTBI and/or TB within prisons published until June 2010; both inmates and prison staff were considered. Studies, which were independently screened by two reviewers, were eligible for inclusion if they reported the incidence of LTBI and TB disease in prisons. Available data were collected from 23 studies out of 582 potentially relevant unique citations. Five studies from the US and one from Brazil were available to assess the incidence of LTBI in prisons, while 19 studies were available to assess the incidence of TB. The median estimated annual incidence rate ratio (IRR) for LTBI and TB were 26.4 (interquartile range [IQR]: 13.0-61.8) and 23.0 (IQR: 11.7-36.1), respectively. The median estimated fraction (PAF%) of tuberculosis in the general population attributable to the exposure in prisons for TB was 8.5% (IQR: 1.9%-17.9%) and 6.3% (IQR: 2.7%-17.2%) in high- and middle/low-income countries, respectively. The very high IRR and the substantial population attributable fraction show that much better TB control in prisons could potentially protect prisoners and staff from within-prison spread of TB and would significantly reduce the national burden of TB. Future studies should measure the impact of the conditions in prisons on TB transmission and assess the population attributable risk of prison-to-community spread. Please see later in the article for the Editors' Summary.

Pulmonary impairment after tuberculosis and its contribution to TB burden

BackgroundThe health impacts of pulmonary impairment after tuberculosis (TB) treatment have not been included in assessments of TB burden. Therefore, previous global and national TB burden estimates do not reflect the full consequences of surviving TB. We assessed the burden of TB including pulmonary impairment after tuberculosis in Tarrant County, Texas using Disability-adjusted Life Years (DALYs).MethodsTB burden was calculated for all culture-confirmed TB patients treated at Tarrant County Public Health between January 2005 and December 2006 using identical methods and life tables as the Global Burden of Disease Study. Years of life-lost were calculated as the difference between life expectancy using standardized life tables and age-at-death from TB. Years lived-with-disability were calculated from age and gender-specific TB disease incidence using published disability weights. Non-fatal health impacts of TB were divided into years lived-with-disability-acute and years lived-with-disability-chronic. Years lived-with-disability-acute was defined as TB burden resulting from illness prior to completion of treatment including the burden from treatment-related side effects. Years lived-with-disability-chronic was defined as TB burden from disability resulting from pulmonary impairment after tuberculosis.ResultsThere were 224 TB cases in the time period, of these 177 were culture confirmed. These 177 subjects lost a total of 1189 DALYs. Of these 1189 DALYs 23% were from years of life-lost, 2% were from years lived-with-disability-acute and 75% were from years lived-with-disability-chronic.ConclusionsOur findings demonstrate that the disease burden from TB is greater than previously estimated. Pulmonary impairment after tuberculosis was responsible for the majority of the burden. These data demonstrate that successful TB control efforts may reduce the health burden more than previously recognized.

Synergistic Pandemics: Confronting the Global HIV and Tuberculosis Epidemics

This supplement was envisioned to summarize the critical issues related to the 2 most deadly infectious diseases worldwide: human immunodeficiency virus (HIV) infection and AIDS and tuberculosis (TB). Together, these infections—1 viral and 1 bacterial, 1 recently emergent and 1 ancient—kill almost 4 million persons every year, most of whom live in developing nations. In tandem, HIV infection and TB create a deadly synergy. TB is the leading cause of death among persons with HIV infection, and areas with a high prevalence of HIV infection have had dramatic increases in the incidence of TB disease. The US government has played a leadership role in addressing the HIV and TB pandemics, most recently through the enactment of the Tom Lantos and Henry J. Hyde United States Global Leadership Against HIV/AIDS, Tuberculosis and Malaria Authorization Act of 2008, which authorized $48 billion over 5 years to combat these deadly infectious diseases in developing nations. We hope that this supplement of scientific review articles focused on HIV infection prevention, TB, and HIV and TB coinfection will serve as a resource for policy makers, HIV and TB program

Interpreting meta-analysis according to the adequacy of sample size. An example using isoniazid chemoprophylaxis for tuberculosis in purified protein derivative negative HIV-infected individuals

To illustrate the utility of statistical monitoring boundaries in meta-analysis, and provide a framework in which meta-analysis can be interpreted according to the adequacy of sample size. To propose a simple method for determining how many patients need to be randomized in a future trial before a meta-analysis can be deemed conclusive. Prospective meta-analysis of randomized clinical trials (RCTs) that evaluated the effectiveness of isoniazid chemoprophylaxis versus placebo for preventing the incidence of tuberculosis disease among human immunodeficiency virus (HIV)-positive individuals testing purified protein derivative negative. Assessment of meta-analysis precision using trial sequential analysis (TSA) with LanDeMets monitoring boundaries. Sample size determination for a future trials to make the meta-analysis conclusive according to the thresholds set by the monitoring boundaries. The meta-analysis included nine trials comprising 2,911 trial participants and yielded a relative risk of 0.74 (95% CI, 0.53-1.04, P = 0.082, I(2) = 0%). To deem the meta-analysis conclusive according to the thresholds set by the monitoring boundaries, a future RCT would need to randomize 3,800 participants. Statistical monitoring boundaries provide a framework for interpreting meta-analysis according to the adequacy of sample size and project the required sample size for a future RCT to make a meta-analysis conclusive.

Incidence of Tuberculosis Disease and Latent Tuberculosis Infection in Patients with End Stage Renal Disease in an Endemic Region

Aim. Patients in chronic renal failure suffer impaired cellular immunity and have an increased risk of tuberculosis (TB). Our aim in this multicenter study was to determine the incidence of TB and to evaluate latent tuberculosis infection (LTBI) in hemodialysis patients. Methods. We retrospectively evaluated the frequency of TB in 779 dialysis patients at 13 hemodialysis centers in five different cities in Southeast Turkey. The tuberculin skin test (TST) was conducted in 733 patients to detect LTBI. Results. The mean age of the patients was 51.2 ± 15.9 years; 398 (51.1%) of the patients were female, and 53.9% of patients had a BCG scar. The mean dialysis duration time was 35.1 ± 33.4 months. TB was diagnosed in 34 cases. The incidence rate of TB in patients undergoing hemodialysis was 3.1%. Ten patients had a history of TB before beginning hemodialysis, and 24 patients had a history of TB after beginning hemodialysis. A diagnosis of TB was made based on clinical data in eight patients and microbiologically or pathologically in 26 patients. The median time between the initiation of dialysis to the diagnosis of TB was 11 months. Extrapulmonary TB occurred in 45.8% of cases, and the most common site of involvement was the lymph nodes. The TST was positive in 61.8% of TB patients and in 37.5% of those with no history of TB. Conclusions. The incidence of TB is high in hemodialysis patients, and they should be evaluated periodically to exclude insidious infection and reduce morbidity and mortality.

Latent tuberculosis infections in hard-to-reach drug using population – detection, prevention and control

Interferon-gamma release assays (IGRAs) need be evaluated for effectiveness as screening tests for tuberculosis (TB) infection in drug users. These tests have demonstrated improved sensitivity and specificity, but have not been studied in drug users. These one step blood tests are intended to replace the tuberculin skin test (TST), which is difficult to use and requires 48 hour follow-up, so they are expected to be particularly suitable for risk groups, like drug users, in whom follow-up is problematic. Drug users have traditionally been identified as being at increased risk for acquiring TB disease. The results of our pilot study using the TST and simpler and more sensitive interferon-gamma release assays showed that about 45% of current drug users in Houston tested have at least one test positive for latent tuberculosis infection (LTBI). These preliminary data suggest that there is an important reservoir of LTBI in drug using populations, and the risk of progression to active TB disease with other infections is great. However, LTBI in drug using populations has not been studied in depth and deserves further investigation. We need to evaluate the validity of IGRAs for detection of latent TB infection, the factors associated with LTBI, the incidence and risk for developing active TB disease in drug users and the effectiveness of early treatment of LTBI. We believe that using better tuberculosis screening tools will allow us to more accurately measure the prevalence of latent TB infection and incidence of active TB disease in drug using populations and develop more effective TB prevention and treatment interventions in the community.

La tuberculose à la Réunion : caractéristiques épidémiologiques issues des déclarations obligatoires, 2000–2007

Located in the South West Indian Ocean, Reunion island is close to countries with a strong incidence of tuberculosis disease: Madagascar, 246 per 100,000, Comoros, 44 per 100,000 or Mayotte, 22 per 100,000 in 2006. However, the epidemiology of tuberculosis in Reunion is poorly documented. Objective This article presents epidemiological characteristics of tuberculosis disease notified between 2000 and 2007 and cases of latent tuberculosis infection for children under 15 years old between 2003 and 2007 in Reunion. Method The data analysed in this article are collected through the mandatory notification. Multi-drug resistant data come from National Reference Centre for Mycobacteria and Antituberculosis Drug Resistance and mortality data from Centre for the epidemiology of medical causes of death in France. Results In Reunion, 495 cases-patients with tuberculosis disease were notified, that is an incidence of eight cases per 100,000 habitants and four cases-patients of latent tuberculosis infection were notified. Regarding tuberculosis disease, the incidence was respectively, 2.4, 6 and 15.9 for the cases-patients aged 0–14, 15–39 and more than 40 years old. Pulmonary tuberculosis accounted for 82% of tuberculosis disease notified cases-patients, 90% of which were microbiologically confirmed. Between 2000 and 2006, the frequency of multidrug-resistant was of 2% (8/423) and the mortality rate was 1.2 per 100,000. Conclusion These results indicate a low incidence in Reunion which can be explained by a low HIV infection incidence (3.2 per 100,000 in 2003–2005), a good standard of hygiene and a good access to care. However, due to migratory fluxes from nearby high incidence countries, the epidemiological surveillance in Reunion must continue and be enhanced to set up the preventive and control measures around the notified cases.

Primary Sternal Tuberculosis Osteomyelitis: A Case Report and Discussion

As immigration to the United States from countries endemic for tuberculosis (TB) increases, the incidence of pulmonary and extrapulmonary TB disease may increase. Primary tuberculous sternal osteomyelitis is one form of extrapulmonary TB that is exceedingly rare throughout the world, and falls under the differential diagnosis for chest wall masses. Management involves standard antituberculous therapy with antibiotics similar to treating other forms of extrapulmonary TB, as well as consideration of surgical intervention depending on the extent of osteomyelitis. A typical case of primary sternal TB osteomyelitis is reported, and the epidemiology, differential diagnosis, clinical manifestations and management are reviewed.

Prevalence of tuberculous infection and incidence of tuberculosis; a re-assessment of the Styblo rule

To evaluate the validity of the fixed mathematical relationship between the annual risk of tuberculous infection (ARTI), the prevalence of smear-positive tuberculosis (TB) and the incidence of smear-positive TB specified as the Styblo rule, which TB control programmes use to estimate the incidence of TB disease at a population level and the case detection rate. Population-based tuberculin surveys and surveys on prevalence of smear-positive TB since 1975 were identified through a literature search. For these surveys, the ratio between the number of tuberculous infections (based on ARTI estimates) and the number of smear-positive TB cases was calculated and compared to the ratio of 8 to 12 tuberculous infections per prevalent smear- positive TB case as part of the Styblo rule. Three countries had national population-based data on both ARTI and prevalence of smear-positive TB for more than one point in time. In China the ratio ranged from 3.4 to 5.8, in the Philippines from 2.6 to 4.4, and in the Republic of Korea, from 3.2 to 4.7. All ratios were markedly lower than the ratio that is part of the Styblo rule. According to recent country data, there are typically fewer than 8 to 12 tuberculous infections per prevalent smear-positive TB case, and it remains unclear whether this ratio varies significantly among countries. The decrease in the ratio compared to the Styblo rule probably relates to improvements in the prompt treatment of TB disease (by national TB programmes). A change in the number of tuberculous infections per prevalent smear-positive TB case in population-based surveys makes the assumed fixed mathematical relationship between ARTI and incidence of smear-positive TB no longer valid.

Prevalence of Tuberculosis Infection in the United States Population

The goal for tuberculosis (TB) elimination in the United States is a TB disease incidence of less than 1 per million U.S. population by 2010, which requires that the latent TB infection (LTBI) prevalence be less than 1% and decreasing. To estimate the prevalence of LTBI in the U.S. population. Interviews and medical examinations, including tuberculin skin testing (TST), of 7,386 individuals were conducted in 1999-2000 as part of the National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of the civilian, noninstitutionalized U.S. population. LTBI was defined as a TST measurement of >/=10 mm. Associations of age, race/ethnicity, sex, poverty, and birthplace were assessed. Results among the 24- to 74-year-old subgroup were compared with NHANES 1971-1972 data. Estimated LTBI prevalence was 4.2%; an estimated 11,213,000 individuals had LTBI. Among 25- to 74-year-olds, prevalence decreased from 14.3% in 1971-1972 to 5.7% in 1999-2000. Higher prevalences were seen in the foreign born (18.7%), non-Hispanic blacks/African Americans (7.0%), Mexican Americans (9.4%), and individuals living in poverty (6.1%). A total of 63% of LTBI was among the foreign born. Among the U.S. born, after adjusting for confounding factors, LTBI was associated with non-Hispanic African-American race/ethnicity, Mexican American ethnicity, and poverty. A total of 25.5% of persons with LTBI had been previously diagnosed as having LTBI or TB, and only 13.2% had been prescribed treatment. In addition to basic TB control measures, elimination strategies should include targeted evaluation and treatment of individuals in high-prevalence groups, as well as enhanced support for global TB prevention and control.

Statistical design of THRio: a phased implementation clinic-randomized study of a tuberculosis preventive therapy intervention

Tuberculosis (TB) is a major public health problem in Rio de Janeiro, where a high proportion of HIV-infected adults are co-infected with latent TB. Health officials in Brazil have recommended that HIV patients be tested for TB infection and given TB prophylaxis (isoniazid) if positive. In practice, although Brazil is a model for provision of antiretroviral therapy to patients with advanced HIV disease, relatively few such patients receive TB testing and prevention services. We initiated a randomized study of a health services intervention to train health personnel in implementation of the recommended routine of TB testing and isoniazid prophylaxis. The primary goal is to reduce incident TB disease in the HIV clinic population. The clinic-level intervention will be phased in gradually over the study period until all clinics have received the intervention. The clinics' order of initiation of intervention was randomized and subjected to constraints based on clinic-level covariates. This phased intervention cluster-randomized trial required special attention to power/sample size calculation and randomization procedures, of which we provide the relevant details. Special design considerations accounted for within-clinic correlation, variation in the clinic size, time-varying ratio of intervention to control clinics and guaranteed post-randomization covariate balance. These were successfully implemented for the estimation of power and execution of the randomization strategy. Although the design features of randomization by clinic and phased implementation of the intervention meet logistic and local needs, they substantially lower the statistical power of the study. Studies with cluster-randomized order of intervention introduction can provide useful information on intervention effects. Their design and analysis are more complicated than for individually randomized parallel design trials. The methods we describe represent practical approaches to the challenges raised in the course of designing this study.

Tuberculosis among Health-Care Workers in Low- and Middle-Income Countries: A Systematic Review

BackgroundThe risk of transmission of Mycobacterium tuberculosis from patients to health-care workers (HCWs) is a neglected problem in many low- and middle-income countries (LMICs). Most health-care facilities in these countries lack resources to prevent nosocomial transmission of tuberculosis (TB).Methods and FindingsWe conducted a systematic review to summarize the evidence on the incidence and prevalence of latent TB infection (LTBI) and disease among HCWs in LMICs, and to evaluate the impact of various preventive strategies that have been attempted. To identify relevant studies, we searched electronic databases and journals, and contacted experts in the field. We identified 42 articles, consisting of 51 studies, and extracted data on incidence, prevalence, and risk factors for LTBI and disease among HCWs. The prevalence of LTBI among HCWs was, on average, 54% (range 33% to 79%). Estimates of the annual risk of LTBI ranged from 0.5% to 14.3%, and the annual incidence of TB disease in HCWs ranged from 69 to 5,780 per 100,000. The attributable risk for TB disease in HCWs, compared to the risk in the general population, ranged from 25 to 5,361 per 100,000 per year. A higher risk of acquiring TB disease was associated with certain work locations (inpatient TB facility, laboratory, internal medicine, and emergency facilities) and occupational categories (radiology technicians, patient attendants, nurses, ward attendants, paramedics, and clinical officers).ConclusionsIn summary, our review demonstrates that TB is a significant occupational problem among HCWs in LMICs. Available evidence reinforces the need to design and implement simple, effective, and affordable TB infection-control programs in health-care facilities in these countries.

International Travel with Children

International Travel with Children

The spectrum of tuberculosis in dialysis patients

Patients receiving dialysis therapy are known to be at increased risk of tuberculosis (TB). The aim of this study was to evaluate the frequency, clinical characteristics and course of TB disease in dialysis patients treated at our institution. Medical records of 330 regular haemodialysis (n=219) and continuous ambulatory peritoneal dialysis (n=111) patients (172 male, 158 female; mean age 55+/-16 y) who were cared for at our tertiary university hospital between December 2002 and January 2006 were retrospectively evaluated. Nine cases of TB (2.7%) occurred, in the following locations: vertebra (n=3), miliary (n=3), lymph nodes (n=1), peritoneum (n=2; one as peritionitis, 1 as an abscess). Four of these 9 patients died during the follow-up (mean time from diagnosis to death, 7 months); none of the deaths appeared to be caused by the disease itself. The incidence of TB disease in patients receiving renal replacement therapy is high, and occurs primarily in extrapulmonary sites.