Factors that influence current tuberculosis epidemiology

Tuberculosis (TB) is a major public health concern worldwide: despite a regular, although slow, decline in incidence over the last decade, as many as 8.6 million new cases and 1.3 million deaths were estimated to have occurred in 2012. TB is by all means a poverty-related disease, mainly affecting the most vulnerable populations in the poorest countries. The presence of multidrug-resistant strains of M. tuberculosis in most countries, with somewhere prevalence is high, is among the major challenges for TB control, which may hinder recent achievements especially in some settings. Early TB case detection especially in resource-constrained settings and in marginalized groups remains a challenge, and about 3 million people are estimated to remain undiagnosed or not notified and untreated. The World Health Organization (WHO) has recently launched a new global TB strategy for the "post-2015 era" aimed at "ending the global TB epidemic" by 2035. This strategy is based on the three pillars that emphasize patient-centred TB care and prevention, bold policies and supportive systems, and intensified research and innovation. This paper aims to provide an overview of the global TB epidemiology as well as of the main challenges that must be faced to eliminate the disease as a public health problem everywhere.

Enfermedades Infecciosas y Microbiología Clínica, 2011

Journal of Infectious Diseases, 2012

Seminars in Respiratory and Critical Care Medicine, 2013

Tuberculosis (TB) was the underlying cause of 1.3 million deaths among human immunodeficiency virus (HIV)-negative people in 2016, exceeding the global number of HIV/acquired immune deficiency syndrome (AIDS) deaths. In addition, TB was a contributing cause of 374,000 HIV deaths. Despite the success of chemotherapy over the past seven decades, TB is the top infectious killer globally. In 2016, 10.4 million new cases arose, a number that has remained stable since the beginning of the 21th century, frustrating public health experts tasked to design and implement interventions to reduce the burden of TB disease worldwide. Ambitious targets for reductions in the epidemiological burden of TB have been set within the context of the Sustainable Development Goals (SDGs) and the End TB Strategy. Achieving these targets is the focus of national and international efforts, and demonstrating whether or not they are achieved is of major importance to guide future and sustainable investments. This article reviews epidemiological facts about TB, trends in the magnitude of the burden of TB and factors contributing to it, and the effectiveness of the public health response.

Social Science & Medicine, 2009

The main thrust of the World Health Organization's global tuberculosis (TB) control strategy is to ensure effective and equitable delivery of quality assured diagnosis and treatment of TB. Options for including preventive efforts have not yet been fully considered. This paper presents a narrative review of the historical and recent progress in TB control and the role of TB risk factors and social determinants. The review was conducted with a view to assess the prospects of effectively controlling TB under the current strategy, and the potential to increase epidemiological impact through additional preventive interventions. The review suggests that, while the current strategy is effective in curing patients and saving lives, the epidemiological impact has so far been less than predicted. In order to reach long-term epidemiological targets for global TB control, additional interventions to reduce peoples' vulnerability for TB may therefore be required. Risk factors that seem to be of importance at the population level include poor living and working conditions associated with high risk of TB transmission, and factors that impair the host's defence against TB infection and disease, such as HIV infection, malnutrition, smoking, diabetes, alcohol abuse, and indoor air pollution. Preventive interventions may target these factors directly or via their underlying social determinants. The identification of risk groups also helps to target strategies for early detection of people in need of TB treatment. More research is needed on the suitability, feasibility and cost-effectiveness of these intervention options.

The Lancet

this decline reflects a substantial progress in the number of patients diagnosed and treated. Moreove, it aslo occurred as poverty-related drivers of TB decreased and economies grew. As evidence of this Ethiopia, Viet Nam, Zimbabwe and Côte d'Ivoire all achieved annual average rates of decline in TB mortality of more than 6% between 2000 and 2017 (Table 1). This progress aside, however, TB mortality rates, especially among people living with HIV and in children are still substantial. 5,6 Furthermore, rates of TB mortality have declined much more slowly than for most other infectious diseases (Appendix Table xx), and the declines are far less in lowand lower-middle income countries compared with elsewhere (Table 2). Three-quarters of all TB deaths occur within just eight countries (Appendix Figure xx). In many parts of sub-Saharan Africa and Southeast Asia, TB remains a leading cause of years-of-life lost. Moreover, TB ranks as the 9 th leading cause of death and the 12 th leading cause of years-of-life lost worldwide. 7 TB incidence: An estimated 10 million people (90 percent adults, 58 percent male) became ill with TB in 2017. Eight countries in Southeast Asia and Africa (India, Indonesia, China, the Philippines, Pakistan, South Africa, Bangladesh and Nigeria) accounted for two-thirds of all new cases worldwide. Overall, TB incidence has fallen approximately 1.4% per year since 2000 and 2% per year since 2015-far less than the rate needed to achieve WHO End TB targets 5 (an annual incidence rate decline of 4-5% by 2020 and 10% by 2025 to achieve the milestone case reductions) and less than declining trends in mortality. The overall slow decline in TB burden suggests that TB programs, while reducing deaths, are insufficient to overcome poverty-related drivers that substantially impact the epidemic. 8 Modeling suggests that to avert transmission, individuals at risk must be identified and provided effective preventive therapy, and individuals with less infectious, early TB must be diagnosed and provided immediate treatment. 9,10 TB Prevalence: Between 2000 and 2016, 32 national TB prevalence surveys were performed in 26 countries. 5 These studies consistently found a higher prevalence of TB than previous estimates based on less precise information such as case notifications. The upwardly revised incidence estimates highlighted large numbers of undiagnosed or unreported TB cases in many countries. Prevalence surveys also revealed that people with TB often sought care for TB symptoms that health care workers failed to identify. Other individuals did not recognize the seriousness of their symptoms and had not sought care. All prevalence surveys in the last decade have found a higher burden of TB among men, with male:female ratios ranging from 1.2 (in Ethiopia) to 4.6 (in Viet Nam). 5 The higher global disease burden in men-estimated to be 1.8 times higher than in women 5-combined with larger detection and THE LANCET COMMISSION ON TUBERCULOSIS 5 reporting gaps highlight gender differences in accessing care that may be related to both financial barriers and stigma. 11 The differences also suggest that male-friendly strategies to improve access to and use of health services are required. Why haven't we made more progress over the last quarter century? The lack of progress against TB over the last 25 years has resulted from a mix of political, societal, scientific, and strategic shortcomings. These include health system frailties; lack of investment in control efforts, and in research towards developing new medical tools; reliance on simplified, one-size-fits-all approaches that fail to meet the different needs of individual patients; biological factors, such as HIV coinfection and the spread of drug resistance; and the huge and persistent reservoir of latent TB infection are all to blame. Moreover, TB is also 'a disease of the shadows,' disproportionately affecting those communities with the least powerful constituencies to effect change. Lack of investment and political will-Deaths from TB fell rapidly in western Europe and the United States as living standards improved. The combination of a decline in TB cases in high-income countries and the lack of a powerful civil society voice in high-burden countries has undermined efforts to garner the same political support or domestic investment as for other diseases. Failure to appreciate the profound negative economic impact of the epidemic and advocate for increased donor financing in highburden, low-income countries has hampered efforts. In many of the highest burden countries, chronic under-funding and lack of political will have profoundly disabled TB programs, and also explain why, 40 years after the Alma Ata Declaration, 13 half the world's population still lacks access to comprehensive health care services. Under-investment in TB research and development-Funding for TB R&D has been stagnant for many years, despite that TB remains a major global health threat. 3 A reflection of this under-investment is the continued reliance upon tools such as smear microscopy and the BCG vaccine developed nearly a century ago. 14 While global funding for TB research received more funding in 2018 than ever before ($772 million), the pace at which scientific discovery progresses has been greatly hindered by lack of sufficient funding dedicated to research priorities that have been defined ad nauseam. 15-17 THE LANCET COMMISSION ON TUBERCULOSIS 6 Broken care cascades and poor quality of care-Turning the tide on TB requires early, accurate case detection together with the rapid initiation of and adherence to effective treatment that prevents Mtb transmission, especially in high-burden countries. To achieve this, national TB programs in such settings must first invest to ensure that all patients with TB seeking care have access to TB diagnostics and treatments. Unfortunately,TB care is frequently delivered with little attention to patient needs and preferences, poorly coordinated with other services, and undermined by lack of access to essential services. 18 A recent assessment of patient pathways in 13 countries accounting for 92% of the world's missed TB cases revealed that even among people who actively sought care, fewer than one-third sought care at a facility that had the capacity to diagnose and/or treat people with TB. 18-21 Referral systems to access diagnostic technologies also were limited. These findings confirm those of numerous other studies from various settings demonstrating the many programmatic and financial barriers 22,23 that prevent people with TB from accessing healthcare. 24 Furthermore, they highlight how it is critical to align the availability of services to where people seek care. Not only is access highly variable, so too is the quality of TB care in many high-burden countries. Although the DOTS strategy emphasized the importance of quality-assured drugs and diagnostics, it neglected to ensure prioritizing the quality of TB care. The Lancet Global Health Commission on High-Quality Health Systems (HQSS) recently highlighted that the vast majority of TB deaths result from poor quality care.. 25. As Figure 1 demonstrates, the care quality is undermined by chronic under-funding, limited access to new tools, and inadequate implementation of policies. Numerous studies have highlighted substantial gaps in the TB care continuum for all forms of TB cases: active disease, DR-TB, latent infection, and childhood TB. 26-30 For patients with multidrug-resistant TB (MDR-TB), only 14% completed treatment, and 11% remained disease-free at one year. A similar study in South Africa found that only 82% of 532,005 TB cases were diagnosed, and less than 54% of drugsusceptible TB cases completed treatment. 29 Of those with rifampicin-resistant TB, only 22% completed treatment (Appendix Figure xx). Simulated patient studies in three countries show that most primary care providers are unable to diagnose TB and referral linkages to the National TB Program (NTP) are weak. In India, China and Kenya, only 28% to 45% of simulation patients were correctly managed by primary care providers. 31-33 Simply put, the current global capacity to diagnose, link to care, treat, and cure TB patients is woefully inadequate for the massive burden of disease that exists. The public health implications, as well as the THE LANCET COMMISSION ON TUBERCULOSIS 7 poor clinical and financial implications 34 for patients, are self-evident. Substantially reducing TB mortality and incidence will require significantly increasing both the coverage and the quality of TB services across the entire care continuum. Failures to optimize private sector engagement Of the 3.6 million unreognized or "missing" TB patients in 2017, 63% of them are in six countries where primary care is dominated by private providers and >67% of initial care-seeking is in the private sector (Table 3). However, in these countries, private provider notifications are just 18% of total TB notifications and 9% of estimated TB incidence. Based on data from TB prevalence surveys and private sector drug sales, 35 a considerable proportion of TB patients are treated in the private sector, with largely unknown levels of quality and patient outcomes.. Given the dominance of private health care in countries with the largest share of "missing" TB patients, to meet national and indeed global TB goals, private providers must be engaged to provide high-quality, patient-centered care on a scale equal to their role in primary care. Modeling studies also suggest that untreated or poorly-treated patients in the private sector are a major source of Mtb transmission. 36 This is due to delay in diagnosis and treatment initiation among private patients, as well as recurrent TB among private patients who were inadequately treated. Therefore, improving the diagnosis and treatment of patients seeking care in private facilities is an opportunity to rapidly reduce TB...

Global Journal of Health Science, 2011

Pulmonary Tuberculosis (TB or tubercle bacillus) is increasing in global prevalence, and greatly threatens the populations of developed and developing countries. Although TB is often associated with developing countries, this communicable condition is currently on the rise in the United States, and elsewhere in the developed world. The proliferation of TB is a result of inadequacies or the non-existence of appropriate and decisively responsive intervention strategies and programs. Moreover, failure to employ adequate procedural response to diseases is heightened by insufficient knowledge of those afflicting communities globally. Practitioners are further challenged in the prevention of TB as a result of reported cases in developing countries being largely incomplete. Whereas one-third of the world's population, or two billion people are currently infected with the tubercle bacillus aerobic bacterium, it is expected that the number of TB-related deaths will rise from three million per year to five million by 2050 (World Health Organization, [hereafter, WHO], 2010).

Journal of Ayub Medical College, Abbottabad : JAMC

Despite the fact that Directly Observed Treatment Strategy (DOTS) short course is cost effective and universally recommended by WHO for effective TB control, it is beyond the financial reach of several highly endemic countries. This article aims at identifying barriers in DOTS's implementation and progress in 22 high burden countries (HBCs) from TB. Medline abstracts, published papers and WHO reports were retrieved, critically examined and compared keeping standard parameters of TB control in view. The increasing caseload, morbidity and mortality due to TB in high burden countries have become a major health challenge and threat to the health systems. The escalated burden of disease and deaths due to TB has posed a great threat to the international security. In the last decade little progress has been witnessed in the implementation of WHO's recommended strategy called DOTS in the 22 high burden countries. Afghanistan, Pakistan, India, Brazil, Zimbabwe, S. Africa and Uganda a...