Number Of TB Cases Research Articles

Scope of Biochemical Markers in Tuberculosis

Tuberculosis is one of the major causes of the mortality from single infectious agent worldwide. India has the highest number of TB cases in the world. It is the leading cause of death, because of its high mortality and morbidity because of the disease, is due to emergence of multidrug resistant TB strains, and the HIV infection which reactivates the latent TB making it more severe. Moreover, failure to diagnose TB early remains one of the primary hurdles in controlling of the disease. The disease is diagnosed generally by its symptoms, radiographic methods, and sputum smear microscopy and by cultivation of the Mycobacterium Tuberculosis, which is considered as gold standard. Current advances in molecular biology and molecular epidemiology and a better understanding of drug resistance in TB have given a new horizon to its rapid diagnosis. However the cost effective techniques, and their requirement for sophisticated equipments & skilled personals have excluded their implementation on a routine basis especially in low income countries.

Measurement of ESAT6-induced IFNγ responses adjunct with CXCL9 increases the rate of diagnosis of active tuberculosis in an endemic region

Due to difficulties in direct diagnosis of Mycobacterium tuberculosis infection where site-specific specimens are not available, indirect methods of testing for infection are required. M. tuberculosis early secreted antigen target-6 (ESAT6) induced IFN-γ responses are specific, but do not differentiate between latent and active TB. The use of adjunct biomarkers for TB diagnosis has been proposed, such as the chemokines: CXCL9, CXCL10 and CCL2.ESAT6-induced IFN-γ CXCL9, CXCL10 and CCL2 was measured in whole blood cell supernatants of patients with pulmonary tuberculosis (PTB, n=36) and extrapulmonary TB (ETB, n=31) and compared with healthy endemic controls (EC, n=33).ESAT6-induced IFN-γ responses were positive in 32% of TB cases as compared with 15% of EC cases (p=0.048). ESAT6-induced CXCL9 responses were positive in 42% of TB cases and 15% of EC cases (p=0.006). ESAT6-induced-CXCL10 and -CCL2 responses did not discriminate between TB and EC groups. Measurement of IFN-γ or CXCL9 together diagnosed TB (53%) cases and was significant as compared with EC (p=0.014) cases. IFN-γ and CXCL10 together did not increase the number of TB cases diagnosed.Within TB groups, ESAT6-IFN-γ/CXCL9-based detection increased to 53% in PTB (p=0.031) and 54% in ETB (p=0.021), with comparable diagnosis in less severe extrapulmonary TB (L-ETB, 55%) and severe disseminated extrapulmonary TB (D-ETB, 50%). Given that 47% of TB cases remained undetected, this study shown that ESAT6-induced IFNγ and CXCL9 can support diagnosis, but must be supported by clinical correlation and other relevant investigations.

Healthcare Worker Behavior and Workflow Changes for the Care of Patients in Isolation Precautions

mentation, reevaluation, and then final documentation. For staff members who require a second reminder letter, or forget to return for the reading, more time is required. After analyzing 5 consecutive years of data and review of NJ State TB Risk Assessment guidelines, our team concluded that we are designated a low risk facility for TB. Our hospital had no newly diagnosed TB patients, zero employee exposures, zero employee conversions and a total of 5 TB patients for the entire county. PROJECT: Our Infection Prevention and Control Committee reviewed the 2005 CDC guidelines for preventing transmission of M. tuberculosis in health-care facilities. The document states: “the recommended frequency of testing of employees for M. tuberculosis infection varies, depending on the institution’s level of risk.” One of our ID physician champions and chair of our Antibiotic Stewardship Committee drafted a letter to the NJ State TB Program Director requesting to re-evaluate the need for annual employee TB testing based upon our historically low TB rates and low-risk designation for five uninterrupted years. RESULTS: In April 2012 we received the approval to suspend our annual employee screening. This decision was based on the historically low number of TB cases treated at the hospital, and the low probability of an exposure to undiagnosed TB due to low incidence in the community. Upon approval, our TB Control Program Plan was modified to include: providing the initial twostep employee Mantoux Tuberculin Skin test for new hires, developing an annual employee TB symptom assessment completed with annual N95 mask fit testing and an expanded contact investigation procedure for any future exposures. Our new TB control plan included the annual TST screening must resume if the criterion for “medium risk” is reached in any subsequent year. LESSON LEARNED: Resources are being stretched to their limits due to growing state and federal mandates and reporting requirements. Programs must reevaluate their current scope of services and surveillance practices to be in compliance with added regulations. Hospitals with a low TB risk category may benefit from reexamining Tuberculosis data to determine if annual TB practices that can be safely stopped.

Epidemiological analyses of tuberculosis in Archangelsk, Russia and implementation of a rapid assay for detection of resistance in this high burden setting

BackgroundTuberculosis (TB) is a major problem in Russia, particularly regarding multidrug-resistant tuberculosis (MDR-TB). Rapid drug susceptibility testing methods are therefore needed. ObjectivesTo perform epidemiological analyses of TB in the Archangelsk region and to evaluate the molecular method GenoType®MTBDRplus in this type of setting. Materials and methodsClinical and microbiological data of all TB patients in Archangelsk were collected in 2010. Smear-positive sputa were analysed by MTBDRplus and Bactec MGIT 960. ResultsThe number of TB cases was 812 (incidence 65/105) and among these patients, 151 cases were registered in the penitentiary system (incidence 1162/105). Most patients were men, 94% had pulmonary TB and 22% were relapses. Out of all cases, 341 (42%) were smear positive and thus contagious and 176 (22%) had MDR-TB, among which one had extensively drug resistant tuberculosis (XDR-TB). Furthermore, two TB patients had strains being resistant to rifampicin, but susceptible to isoniazid. The number of cases being both contagious and MDR-TB was 128 representing 15.8% of all TB cases (incidence 10.2/105). Among these 128 TB patients 37 were relapses representing 25.7% of all the relapse cases. The results of MTBDRplus and Bactec MGIT analyses corresponded in 98.8%. ConclusionsIn Archangelsk many TB patients had contagious MDR-TB thus being hazardous in society and relapsing pulmonary TB was common. The TB situation in the prisons was particularly severe. The analyses showed furthermore that MTBDRplus is of major value in this setting.

P281: Adequacy to the use of personal protective equipment in the isolations of emergency

A growing number of TB cases diagnosed and treated in hospitals, mainly by the association of TB with HIV infection and other immunosuppressive diseases, which poses a risk to health professionals[1]. Thus, they must be prepared to identify suspects and TB patients as early as possible, valuing aspects of prevention and use of security measures.

Recent epidemiological trends in tuberculous pleural effusion in Galicia, Spain

ObjectiveKnowledge on the distribution and determinants of tuberculous pleural effusions (TBPE) is incomplete. We aimed to describe the epidemiological trends and individual characteristics of TBPE in Galicia, Spain, over a 10-year period (2000–2009). DesignA retrospective, observational study based on epidemiological data obtained from the Galician Tuberculosis Register. ResultsThere were 1835 cases of TBPE (16.3% of the total 11,241 TB cases reported). The number and incidence of TBPE decreased significantly during the study period, from (262 and 9.6/100,000 inhabitants in 2000, to 133 and 4.8 in 2009, respectively; P<.001 for both). The mean annual decrease in TBPE incidence was 6.9%, and 50% overall. TBPE mainly affected males (63.5%), precisely 61.2% young males between 15 and 44years. Twenty-five percent had lung involvement (chest X-ray), and 41.7% had a positive sputum culture. A significant increase (P<.001) was observed during the study in the percentage of patients who had more TB risk factors. ConclusionsThe incidence of TBPE decreased significantly during the study period, with no changes in epidemiological characteristics, and with trends similar to the total number of TB cases. The introduction of the Galician Prevention and Control Plan (GPCP) for tuberculosis appears to be effective for better control of TB.

Tuberculosis trends in Saudis and non-Saudis in the Kingdom of Saudi Arabia--a 10 year retrospective study (2000-2009).

BackgroundTuberculosis (TB) remains a public health problem in the Kingdom of Saudi Arabia (KSA), which has a very large labour force from high TB endemic countries. Understanding the epidemiological and clinical features of the TB problem, and the TB burden in the immigrant workforce, is necessary for improved planning and implementation of TB services and prevention measures.MethodsA 10 year retrospective study of all TB cases reported in KSA covering the period 1st January 2000 to 31st December 2009. Data was obtained from TB reporting forms returned to the Ministry of Health. Data were then organised, tabulated and analysed for annual incidence rates by province, nationality, country of origin and gender.ResultsThere was an annual increase in the number of TB cases registered from 3,284 in 2000 to 3,964 in 2009. Non-Saudis had nearly twice the TB incidence rate compared to Saudis (P = <0.05). All but four provinces (Najran, Riyadh, Makkah, Tabuk) showed decreasing TB incidence rates. The highest rates were seen in the 65+ age group. In the 15–24 year age group the incidence rate increased from 15.7/100,000 in 2000 to 20.9/100,00 in 2009 (P = <0.05). The incidence of TB in Saudi males was higher than Saudi females. Conversely, for non-Saudis the TB incidence rates were significantly higher in females compared to males.ConclusionsDespite significant investments in TB control over 15 years, TB remains an important public health problem in the KSA affecting all age groups, and Saudis and non-Saudis alike. Identification of the major risk factors associated with the persistently high TB rates in workers migrating to KSA is required. Further studies are warranted to delineate whether such patients re-activate latent Mycobacterium tuberculosis (M.tb) infection or acquire new M.tb infection after arrival in KSA. Appropriate interventions are required to reduce TB incidence rates as have been implemented by other countries.

The Impact and Cost of Scaling up GeneXpert MTB/RIF in South Africa

ObjectiveWe estimated the incremental cost and impact on diagnosis and treatment uptake of national rollout of Xpert MTB/RIF technology (Xpert) for the diagnosis of pulmonary TB above the cost of current guidelines for the years 2011 to 2016 in South Africa.MethodsWe parameterised a population-level decision model with data from national-level TB databases (n = 199,511) and implementation studies. The model follows cohorts of TB suspects from diagnosis to treatment under current diagnostic guidelines or an algorithm that includes Xpert. Assumptions include the number of TB suspects, symptom prevalence of 5.5%, annual suspect growth rate of 10%, and 2010 public-sector salaries and drug and service delivery costs. Xpert test costs are based on data from an in-country pilot evaluation and assumptions about when global volumes allowing cartridge discounts will be reached.ResultsAt full scale, Xpert will increase the number of TB cases diagnosed per year by 30%–37% and the number of MDR-TB cases diagnosed by 69%–71%. It will diagnose 81% of patients after the first visit, compared to 46% currently. The cost of TB diagnosis per suspect will increase by 55% to USD 60–61 and the cost of diagnosis and treatment per TB case treated by 8% to USD 797–873. The incremental capital cost of the Xpert scale-up will be USD 22 million and the incremental recurrent cost USD 287–316 million over six years.ConclusionXpert will increase both the number of TB cases diagnosed and treated and the cost of TB diagnosis. These results do not include savings due to reduced transmission of TB as a result of earlier diagnosis and treatment initiation.

P1-92 An epidemiological study of tuberculosis patients with risk pattern of HIV/AIDS among underprivileged population in North India

IntroductionTuberculosis is a major cause of morbidity and mortality in developing countries. National AIDS Control Organization, India has reported TB as the commonest opportunistic infection (62.3%) among HIV infected persons.MethodologyThe...

Nutrition, Diabetes and Tuberculosis in the Epidemiological Transition

BackgroundDiabetes prevalence and body mass index reflect the nutritional profile of populations but have opposing effects on tuberculosis risk. Interactions between diabetes and BMI could help or hinder TB control in growing, aging, urbanizing populations.Methods and FindingsWe compiled data describing temporal changes in BMI, diabetes prevalence and population age structure in rural and urban areas for men and women in countries with high (India) and low (Rep. Korea) TB burdens. Using published data on the risks of TB associated with these factors, we calculated expected changes in TB incidence between 1998 and 2008. In India, TB incidence cases would have increased (28% from 1.7 m to 2.1 m) faster than population size (22%) because of adverse effects of aging, urbanization, changing BMI and rising diabetes prevalence, generating an increase in TB incidence per capita of 5.5% in 10 years. In India, general nutritional improvements were offset by a fall in BMI among the majority of men who live in rural areas. The growing prevalence of diabetes in India increased the annual number of TB cases in people with diabetes by 46% between 1998 and 2008. In Korea, by contrast, the number of TB cases increased more slowly (6.1% from 40,200 to 42,800) than population size (14%) because of positive effects of urbanization, increasing BMI and falling diabetes prevalence. Consequently, TB incidence per capita fell by 7.8% in 10 years. Rapid population aging was the most significant adverse effect in Korea.ConclusionsNutritional and demographic changes had stronger adverse effects on TB in high-incidence India than in lower-incidence Korea. The unfavourable effects in both countries can be overcome by early drug treatment but, if left unchecked, could lead to an accelerating rise in TB incidence. The prevention and management of risk factors for TB would reinforce TB control by chemotherapy.

Global situation of TB and its control

Tuberculosis occupies 4th place among major causes of death, and the number of new cases is estimated at 7.25 million in 1997, and 99% of TB deaths and 95% of new TB cases are seen in developing countries. TB had been brought under control in developed countries by applying modern TB control programme including chemotherapy, as basic health infrastructure was already well developed, and their economy can afford cost of control programme including TB drugs. The rapid decline of TB due to the success of TB control in developed countries had lowered the concern on TB, thus bought about the reduction in research grant for TB and difficulty in bringing up successors engaging in TB control. Similar trend was seen also in developing countries, where TB still remains one of most important health problems due to poor quality of the programme caused by poorly developed health infrastructure including man-power, budget and institutions. New obstacles which hinder the smooth implementation of TB control programme have appeared, and they are the rapid expansion of global population, the move of population, the impact of HIV epidemic on TB and the multi-drug-resistant TB (MDRTB). The growth of population automatically increases the number of TB cases and gives heavier burden for TB control. TB has moved from developing to developed countries with the move of the population, and currently approximately half of new TB cases in developed countries is occupied by foreign born patients. Among several opportunistic infections seen in AIDS cases, TB comes out first as the virulence of tubercle bacilli is much higher than the other germs causing opportunistic infections. The pathogenesis of TB changes markedly among HIV positives, and the incidence becomes much higher, and the time interval from the primary infection to the disease, and that from the detection of the disease to death without any effective treatment are shortened, and the fatality rate becomes much higher. Because of the atypical clinical picture, attenuated tuberculin sensitivity and high incidence of side-effects of TB drugs, in particular thiacetazone, clinical management of HIV positive TB is much more difficult than ordinary TB. MDRTB is produce by the bad quality of TB control, and by improving treatment completion rate as well as the cure rate, decline in the prevalence of drug resistance, both primary and acquired, could be expected together with the decline of TB itself. WHO has made a great challenge with TB after the nomination of Dr Kochi to chief medical officer, TUB in 1989. Currently, Global TB Programme (GTB) is promoting so-called DOTS strategy of TB control, consisting of the commitment of the government to give high priority to TB control, passive case-finding with sputum smear examination by microscopy, directly observed treatment by standardized short-course regimen of chemotherapy, well-organized logistics for TB drugs, and the provision of reporting and monitoring system of TB including the evaluation of treatment outcome by cohort analysis. Marked achievements have been obtained in several countries introduced DOTS strategy. Japan is asked to intensify its efforts in international cooperation in TB control.

Estimation of the number of necessary beds for tuberculosis patients, in Japan

To estimate the number of necessary beds for tuberculosis patients in Japan from the view point of isolation of the source of infection. We calculated the number of necessary beds for tuberculosis cases separately for the initial phase and for the chronic excreters. For the initial phase we calculated by multiplying the number of detected tuberculosis cases and the duration of hospitalization. The number of detected cases is based on the figures in 2002 and the duration of hospitalization is assumed to be 90 days for sputum smear positive cases and 60 days for sputum smear negative cases. We calculated the number of necessary beds using the Monte Carlo simulation for each prefecture on the assumption that the incidence and the duration of diseases will be under the effect of random fluctuation with the Poisson's distribution for the number of cases and with the log normal distribution for the duration of hospitalization. We also considered the seasonal fluctuation. Our calculation revealed that around 6,413 beds would be necessary for the initial phase and 200-400 beds for chronic excreters in Japan. There are several prefectures which only requires less than 30 beds. Currently, Japan has around 17,000 beds secured for tuberculosis patients. Our calculation showed that this was much more than needed. In many areas, one ward will provide more than sufficient number of tuberculosis beds. Specialist consultation system must be improved because of the reduction in the number of TB cases treated at hospitals with TB wards and TB specialists. For the treatment of non-infectious TB, ambulatory DOT system, TB shelter and nursing care facilities would be necessary to guarantee compliance to treatment.

The role of entry screening in case finding of tuberculosis among asylum seekers in Norway

BackgroundMost new cases of active tuberculosis in Norway are presently caused by imported strains and not transmission within the country. Screening for tuberculosis with a Mantoux test of everybody and a chest X-ray of those above 15 years of age is compulsory on arrival for asylum seekers.We aimed to assess the effectiveness of entry screening of a cohort of asylum seekers. Cases detected by screening were compared with cases detected later. Further we have characterized cases with active tuberculosis.MethodsAll asylum seekers who arrived at the National Reception Centre between January 2005 - June 2006 with an abnormal chest X-ray or a Mantoux test ≥ 6 mm were included in the study and followed through the health care system. They were matched with the National Tuberculosis Register by the end of May 2008.Cases reported within two months after arrival were defined as being detected by screening.ResultsOf 4643 eligible asylum seekers, 2237 were included in the study. Altogether 2077 persons had a Mantoux ≥ 6 mm and 314 had an abnormal chest X-ray. Of 28 cases with tuberculosis, 15 were detected by screening, and 13 at 4-27 months after arrival. Abnormal X-rays on arrival were more prevalent among those detected by screening. Female gender and Somalian origin increased the risk for active TB.ConclusionIn spite of an imperfect follow-up of screening results, a reasonable number of TB cases was identified by the programme, with a predominance of pulmonary TB.

Bi-directional screening for tuberculosis and diabetes: a systematic review

To assess the yield of finding additional TB or diabetes mellitus (DM) cases through systematic screening and to determine the effectiveness of preventive TB therapy in people with DM. We systematically reviewed studies that had screened for active TB or implemented preventive therapy for TB among people with DM, and those that screened for DM among patients with TB. We searched published literature through PubMed and EMBASE and included studies that reported the number of TB cases identified among people with DM; the number of DM cases identified among patients with TB, or the relative incidence of TB between people with DM who received a TB prophylaxis and those who did not. We assessed the yield of screening by estimating the prevalence of TB or DM in each study, the prevalence ratio and difference where comparison populations were available, and the number of persons to screen to detect an additional case of TB or DM. Twelve studies on screening for TB in people with DM and 18 studies on screening for DM in patients with TB met our inclusion criteria. Screening for TB in persons with DM demonstrated that TB prevalence in this population is high, ranging from 1.7% to 36%, and increasing with rising TB prevalence in the underlying population as well as with DM severity. Screening patients with TB for DM also yielded high prevalences of DM ranging from 1.9% to 35%. Two studies examining the role of TB preventive therapy in people with DM did not provide sufficient details for clear evidence of the effectiveness. Active screening leads to the detection of more TB and DM with varying yield. This review highlights the need for further research in screening and preventive therapy.

Situación de la tuberculosis en Colombia, 2007–2008, con énfasis en los casos pediátricos y su asociación con VIH

ObjectiveTo describe the status of Tuberculosis in Colombia during 2007 and 2008, emphasizing TB-HIV co-infection and pediatric TB behavior. Materials and MethodsThis is a descriptive study. The information source was the National TB Control Program (PNCT in Spanish). Data were collected from the cases and activities quarterly reports and the cohort analysis the national program has implemented in the departments and districts of the country. OutcomesIn 2007 and 2008 a slight increase, from 11,051 to 11,573 cases, in reporting tuberculosis cases of in the country was documented. The most affected age group included patients 25 to 34 years old, and there were more men than women among the reported cases. TB cases in 15 year olds and younger increased from 347 to 419, and the number of patients with TB-HIV coinfection reported to the NTCP doubled; that is, the number of cases went from 218 to 457 from 2007 to 2008. The largest number of cases occurred among men and the 25 to 44 year old group. ConclusionsAn improvement in reporting cases has been observed, as well as an increase in the number of TB cases within the general, pediatric, and TB/HIV populations when comparing 2007 and 2008. In relation to general programmatic indicators, the country did not reach the detection and treatment goals during those years.

False Economies

At last, someone has made the effort of drawing attention to the “forgotten disease” that is tuberculosis, especially to the global catastrophe of increasing drug resistance. At the district hospital in Parsberg—the only closed quarantine hospital for TB in Germany—we have been treating recalcitrant TB patients for more than 40 years; in the past 10 years we have increasingly recorded a substantial increase in the MDR/XDR (multidrug resistant/extensively drug resistant) forms of TB. Since 2008, Germany’s federal states have been contributing to the treatment costs (costs of isolation treatment) because this is state responsibility under the Infection Protection Act. Since then, inpatient occupation has dropped by 50% and the number of TB cases by 70%. My question is: where are these patients being treated now (the incidence has stayed roughly the same)? Or has a penny pinching mentality spread among the health offices and states and false economies applied that would put us all to shame in view of the billions invested in saving the banks? The medical service of the health insurers also examines almost each and every case and increasingly refuses inpatient treatment for such patients (who are difficult to deal with on a personal level as well as from a medical perspective). The demise of our hospital is therefore merely a question of time. But if specialist hospitals, such as ours, with their in-depth knowledge of how to treat drug resistant TB are abolished and the public health services sacrifice their careful approach on the altar of cost savings, the global catastrophe will rapidly become a national catastrophe—albeit a self inflicted one.

THE INFLUENCE OF HEAVY ALCOHOL CONSUMPTION ON HIV INFECTION AND PROGRESSION

The Sub-Sahara African region is inhabited by only 11% of the global population, but is home to 67% of the total HIV infected people and accounts for more than 70% of global AIDS deaths. In this study, we construct a mathematical model to investigate the effect of heavy alcohol consumption on the transmission and progression of HIV/AIDS, and to assess the impact of heavy drinkers on HIV/AIDS related social and health problems such as TB case load and number of orphans. Using demographic data for Botswana, we have shown that if more HIV/AIDS individuals had been de-addicted from heavy alcohol consumption, the severity of the HIV/AIDS epidemic and the impact of HIV/AIDS on the number of TB cases and orphans would have been significantly less than is the case currently. The study points to the vital need for counseling and education about the evils of heavy alcohol consumption and for alcohol de-addiction programmes.

Treinamento da equipe de saúde e busca ativa na comunidade: estratégias para a detecção de casos de TB

To evaluate the impact that Family Health Program (FHP) team training and active surveillance have on the detection of TB cases in a low-income community in the city of Fortaleza, Brazil. The study was performed in an area with approximately 25,000 inhabitants, served by a health care center with five FHP teams, in the city of Fortaleza, Brazil. Although all of the teams were trained, active surveillance was carried out only in one of the areas (area 5). We compared the number of TB cases detected in each of the five areas prior to and after the intervention. We also compared the number of TB cases detected in area 5 to the number of those detected in the other areas, as well as to the citywide number of reported TB cases in Fortaleza, within the same period. The number of TB cases detected in the area studied increased from 1 in 2002 to 22 in 2004 (p < 0.05). There was no significant difference between the number of TB cases in area 5 and that observed for each of the other four areas (p > 0.05). There was a significant increase in the number of TB cases detected in the area studied when compared to the city as a whole (p < 0.05). Training and sensitization of FHP professionals were effective in promoting an increase in the number of TB cases detected in a low-income community.

Incidência de TB diagnosticada no pronto-atendimento de um hospital escola na região sudeste do Brasil

In this study, we analyzed the number of TB cases in an emergency room (ER) and the susceptibility profile of Mycobacterium tuberculosis strains. Patients were selected from among those treated at the Hospital das Clínicas, in the city of Belo Horizonte, Brazil. Between 2002 and 2005, 240 TB patients were identified. Of those, 117 patients (48.7%) were diagnosed in the ER, 72 (61.5%) presenting positive sputum smear microscopy. Drug susceptibility testing was carried out in 90 strains, of which 80 (89%) were sensitive, 9 (10%) were resistant, and 1 (1%) was multidrug resistant. The incidence of positive smear sputum microscopy and resistant TB strains was high, which calls for the immediate adoption of TB control measures in the ER.

Overcoming the Limits of Tuberculosis Prevention among Foreign-Born Individuals: Next Steps toward Eliminating Tuberculosis

From 1993 through 2006 the number of TB cases in the United States decreased by 45% from 25108 to 13767. However the decrease has occurred disproportionately among the US-born population in which the number of cases has decreased by 66%. Over the same interval the number of foreign-born TB cases in the United States actually increased by 5%. In 2006 57% of all TB cases reported were among foreign-born persons. If current trends continue this proportion will continue to grow and we could reach a point at which TB is nearly eliminated among US-born persons but is still a major problem among foreign-born individuals. Similar trends have been noted in other countries with a low burden of TB; in several European countries greater than 50% of TB cases occur among foreign-born persons. These trends raise a fundamental question: why do current TB-control strategies have such limited impact on the foreign-born population? The article by Walter et al. complements previously published evidence to provide some answers to this question and to guide future efforts to control and eliminate TB. (excerpt)