Improvements are needed in current screening, which is insufficient and ineffective.

In industrialized countries, tuberculosis (TB) cases are concentrated among immigrants and driven by reactivation of imported latent TB infection (LTBI). We examined mechanisms used to screen immigrants for TB and LTBI by sending an anonymous, 18-point questionnaire to 31 member countries of the Organisation for Economic Co-operation and Development. Twenty-nine (93.5%) of 31 responded; 25 (86.2%) screened immigrants for active TB. Fewer countries (16/29, 55.2%) screened for LTBI. Marked variations were observed in targeted populations for age (range <5 years of age to all age groups) and TB incidence in countries of origin of immigrants (>20 cases/100,000 population to >500 cases/100,000). LTBI screening was conducted in 11/16 countries by using the tuberculin skin test. Six countries used interferon-γ release assays, primarily to confirm positive tuberculin skin test results. Industrialized countries performed LTBI screening infrequently and policies varied widely. There is an urgent need to define the cost-effectiveness of LTBI screening strategies for immigrants.

A systematic review by Iacopo Baussano and colleagues synthesizes published research to show that improved tuberculosis (TB) control in prisons could significantly reduce the burden of TB both inside and outside prisons.

Background

Transmission of tuberculosis (TB) in prisons has been reported worldwide to be much higher than that reported for the corresponding general population.

Methods and Findings

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.

Conclusions

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

Editors' Summary

Background

Every year, nearly 10 million people develop tuberculosis (TB)—a contagious bacterial infection usually of the lungs—and nearly two million people die from the disease. TB is caused by Mycobacterium tuberculosis, which spreads in airborne droplets when people with the disease cough or sneeze. Most people infected with M. tuberculosis never become ill—their immune system contains the infection. However, the bacteria remain dormant (latent) within the body, and a latent TB infection (LTBI) can cause active disease many years after the initial infection if host immunity declines. The symptoms of TB include a persistent cough, weight loss, and night sweats. Infection with M. tuberculosis can be diagnosed using the tuberculin skin test; tests for TB itself include chest X-rays and sputum cultures (in which bacteriologists try to grow M. tuberculosis from sputum samples, mucus brought up from the lungs by coughing). TB can usually be cured by taking several powerful antibiotics daily for several months.

Why Was This Study Done?

Last century, global control efforts began to reduce the incidence (number of new cases in a population in a given time) and prevalence (the number of affected people in a population) of LTBI and TB in many countries. Now, the emergence of antibiotic-resistant bacterial strains is thwarting these efforts. Consequently, it is important to identify settings where TB transmission is particularly high. One such setting is thought to be prisons. In these facilities, overcrowding, late case detection, inadequate treatment, and poor implementation of infection control measures (including incomplete segregation of people with active TB) might increase the TB transmission rate. However, it is not known how many people in prison become infected with M. tuberculosis or develop TB each year compared to the general population nor what percentage of LTBI and TB in the general population is attributable to exposure to M. tuberculosis in prison (the population attributable fraction or PAF%). Here, the researchers undertake a systematic review (a study that uses predefined criteria to identify all the research on a given topic) to investigate the incidence of TB in prisons.

What Did the Researchers Do and Find?

The researchers identified 23 studies that reported the incidence of LTBI and/or TB in prisons among both staff and prisoners. They estimated the incidence of TB in relevant general populations using World Health Organization data; estimates of the incidence of LTBI in the general population came from the studies themselves. The researchers then calculated the ratio between the incidence rates for LTBI and TB in prison and in the general population (incidence rate ratios or IRRs) for each study. For both LTBI and TB, the IRR varied widely between studies. The average IRR for LTBI was 26.4. That is, the average incidence of LTBI in prisons was 26.4 times higher than in the general population; the average IRR for TB was 23.0. The researchers also estimated the fraction of TB in the general population attributable to within-prison exposure to M. tuberculosis for each study. Again, there was considerable heterogeneity between the studies but, on average, the PAF% for TB in high-income countries was 8.5% (that is, one in 11 cases of TB in the general population was attributable to within-prison spread of TB); in middle-to-low–income countries, the average PAF% was 6.3%.

What Do These Findings Mean?

These findings suggest that the risk of LTBI and TB is at least an order of magnitude higher in prisons than in the general population and that the within-prison spread of LTBI and TB is likely to substantially affect the incidence of LTBI and TB in the general population. The accuracy and generalizability of these findings are limited by the small number of studies identified, by the relative paucity of studies from countries other than the USA, by study heterogeneity, and by assumptions made in the calculation of PAF%. Even so, these findings suggest that improvements in TB control in prisons would not only help to protect prisoners and staff from within-prison spread of TB but would also reduce national TB burdens. Further studies are now needed to identify the specific conditions in prisons that influence TB transmission so that rational policies can be developed to improve TB control in correctional facilities.

Additional Information

Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000381.

This study is discussed in the December 2010 PLoS Medicine Editorial

The World Health Organization provides information on all aspects of TB, including information on TB in prisons and on the Stop TB Partnership (some information is in several languages)

The US Centers for Disease Control and Prevention has information about TB and on TB in prisons

The US National Institute of Allergy and Infectious Diseases also has detailed information on all aspects of TB

Background

In industrialised countries, occupational tuberculosis among healthcare workers (HCWs) is re‐emerging as an important public health issue. To prevent and control tuberculosis transmission, several institutions have issued and implemented recommendations and practice guidelines.

Objectives

To estimate the annual rate of tuberculosis infection (ARTI; per 100 person‐years) among HCWs in Turin, the capital of the Piedmont region of Italy, to identify factors associated with variations in the ARTI and to evaluate the efficacy of the regional guidelines to prevent and control tuberculosis.

Methods

The study was conducted between 1997 and 2004 on a cohort of HCWs. The tuberculosis infection was diagnosed through tuberculin skin testing (TST) conversion and defined as an induration increase of at least 10 mm from a previous negative TST. The ARTI and the hazard ratio for each at‐risk subgroup, categorised according to working activities and settings, was estimated using exponential survival models. The efficacy of the regional guidelines was estimated by stratifying the analysis according to the moment of the implementation of the guidelines (before/after).

Results

The 2182 study participants were drawn from the dynamic cohort. The overall adjusted ARTI was 1.6 (95% CI: 1.3 to 1.9)/100 person‐years. Different workplaces (eg, administrative and infectious diseases inpatient services) and occupations (eg, clerical and medical workers) were associated with significantly different ARTIs, ranging between 0.62 and 2.62 and between 0.61 and 1.71, respectively, whereas the TST conversion risk differed by about 16–68% and 30–60%, respectively. The implementation of the guidelines coincided with overall ARTI reductions of 1.3/100 person‐years, and concurrently the variations between ARTIs of different occupations and workplaces disappeared.

Conclusions

The occupational risk categories for targeting the surveillance and prevention of tuberculosis transmission among HCWs were identified, and the introduction of preventive measures was observed to be effective in decreasing the overall risk of tuberculosis infection among HCWs.

Background

Despite national guidelines in 2003 aimed at limiting the recourse to tonsillectomy and/or adenoidectomy (A/T), the latter are among the most frequent pediatric surgeries performed in Italy. Aim of the study is to investigate variability of A/T rates among children of the Veneto Region, Italy.

Methods

All discharges of Veneto residents with Diagnosis-Related Groups 57–60 and ICD9-CM intervention codes 28.2 (tonsillectomy), 28.3 (adenotonsillectomy), 28.6 (adenoidectomy) were selected in the period 2000–2006 for a descriptive analysis. A multilevel Poisson regression model was applied to estimate Incidence Rate Ratios (IRR) with 95% Confidence Intervals (CI) for A/T surgery among children aged 2–9 years in 2004–2006, while taking into account clustering of interventions within the 21 Local Health Units.

Results

Through 2000–2006, the overall number of A/T surgeries decreased (-8%); there was a decline of adenoidectomies (-20%) and tonsillectomies (-8%), whereas adenotonsillectomies raised (+18%). Analyses on children aged 2–9 resulted in an overall rate of 14.4 surgeries per 1000 person-years (16.1 among males and 12.5 among females), with a wide heterogeneity across Local Health Units (range 8.1–27.6). At random intercept Poisson regression, while adjusting for sex and age, intervention rates were markedly lower among foreign than among Italian children (IRR = 0.57, CI 0.53–0.61). A/T rates in the 10–40 age group (mainly tonsillectomies) computed for each Local Health Unit and introduced in the regression model accounted for 40% of the variance at Local Health Unit level of pediatric rates (mainly adenoidectomies and adenotonsillectomies).

Conclusion

A/T rates in the Veneto Region, especially adenoidectomies among children aged 2–9 years, remain high notwithstanding a decrease through 2000–2006. A wide heterogeneity according to nationality and Local Health Units is evident. The propensity to A/T surgery of each Local Health Unit is similar in different age groups and for different surgical indications.

Epidemiology and public health are usually context-specific. Journals published in different languages and countries play a role both as sources of data and as channels through which evidence is incorporated into local public health practice. Databases in these languages facilitate access to relevant journals, and professional education in these languages facilitates the growth of native expertise in epidemiology and public health. However, as English has become the lingua franca of scientific communication in the era of globalisation, many journals published in non-English languages face the difficult dilemma of either switching to English and competing internationally, or sticking to the native tongue and having a restricted circulation among a local readership. This paper discusses the historical development of epidemiology and the current scene of epidemiological and public health journals, databases and professional education in three Western European languages: French, German and Italian, and examines the dynamics and struggles they have today.