Introduction and elimination of Bovine Viral Diarrhoea Virus in a commercial beef herd: a case study

Routine Bovine Viral Diarrhoea Virus (BVDV) monitoring of a commercial beef herd in southern New South Wales over a 10-year period provided an opportunity to assess the impact of the introduction of BVDV on that herd. BVDV antibody testing provided strong evidence that the herd was initially free of BVDV (2009-2011). Testing from 2012 suggested BVDV had been introduced into the herd and this was confirmed in 2015 with the identification of persistently infected (PI) animals. Having become established in the herd, the owners then set out to eliminate BVDV from the herd. Antigen testing aimed at identifying PI animals revealed BVDV was already absent from the herd. Subsequent antibody testing confirmed that the herd was now free from BVDV. Despite the incursion of BVDV in this herd, there was little measurable impact on reproductive performance (pregnancy rates), although suspected increased calf losses from birth to calf marking were reported. This is the first time such self-clearance has been documented as part of a longitudinal study under Australian conditions.

Health System Costs of Treating Latent Tuberculosis Infection With Four Months of Rifampin Versus Nine Months of Isoniazid in Different Settings

BACKGROUND

Four months of rifampin treatment for latent tuberculosis infection is safer, has superior treatment completion rates, and is as effective as 9 months of isoniazid. However, daily medication costs are higher for a 4-month rifampin regimen than a 9-month isoniazid regimen.

OBJECTIVE

To compare health care use and associated costs of 4 months of rifampin and 9 months of isoniazid.

DESIGN

Health system cost comparison using all health care activities recorded during 2 randomized clinical trials. (ClinicalTrials.gov: NCT00931736 and NCT00170209).

SETTING

High-income countries (Australia, Canada, Saudi Arabia, and South Korea), middle-income countries (Brazil and Indonesia), and African countries (Benin, Ghana, and Guinea).

PARTICIPANTS

Adults and children with clinical or epidemiologic factors associated with increased risk for developing tuberculosis that warranted treatment for latent tuberculosis infection.

MEASUREMENTS

Health system costs per participant.

RESULTS

A total of 6012 adults and 829 children were included. In both adults and children, greater health system use and higher costs were observed with 9 months of isoniazid than with 4 months of rifampin. In adults, the ratios of costs of 4 months of rifampin versus 9 months of isoniazid were 0.76 (95% CI, 0.70 to 0.82) in high-income countries, 0.90 (CI, 0.85 to 0.96) in middle-income countries, and 0.80 (CI, 0.78 to 0.81) in African countries. Similar findings were observed in the pediatric population.

LIMITATION

Costs may have been overestimated because the trial protocol required a minimum number of follow-up visits, although fewer than recommended by many authoritative guidelines.

CONCLUSION

A 4-month rifampin regimen was safer and less expensive than 9 months of isoniazid in all settings. This regimen could be adopted by tuberculosis programs in many countries as first-line therapy for latent tuberculosis infection.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research.

Knowledge, attitudes and management of bovine viral diarrhoea virus among eastern Australian cattle producers: results from a 2013 cross-sectional study

Bovine viral diarrhoea virus (BVDV) is an economically significant disease affecting the Australian cattle industry, with losses stemming from decreased production and reproductive performance and control costs. However, these losses can be difficult to appreciate, particularly in endemic regions. Overall, there is a variable but high herd-level seroprevalence in Australia. Despite a potentially high financial burden of the disease, the onus for control ultimately falls on producers and strategies employed will vary between regions. A cross-sectional study, using a postal survey, was conducted in 2013 to evaluate the BVDV knowledge, attitudes and management practices utilised by Australian cattle producers. A total of 192 producers participated in the study, and results indicate that knowledge and attitudes towards disease risk are variable and can be improved. Producer knowledge of how persistently infected (PI) animals are produced was higher than that of disease outcomes or transmission pathways. Implementation of biosecurity practices was limited, with approximately half of respondents employing quarantine procedures for introduced stock and only 2% indicating they would antigen test introduced stock for BVDV. Approximately a third (36%) of producers reported engaging in BVDV control, with the majority of these using vaccination strategies over deliberate exposure to a PI. Knowledge of and engagement with BVDV control was positively influenced by the producer relationships with veterinarians. Findings from this study suggest that building on education and delivering a consistent message among stakeholders would likely improve producer awareness and understanding in relation to BVDV and support decision making in BVDV management.

Prompt recognition of infectious pulmonary tuberculosis is critical to achieving elimination goals: a retrospective cohort study

INTRODUCTION

All pulmonary tuberculosis (PTB) cases are presumed to be infectious to some degree. This spectrum of infectiousness is independently described by both the acid-fast bacilli smear and radiographic findings. Smear-positive patients with chest radiographic findings that are typical for adult-type PTB are believed to be most infectious.

HYPOTHESIS

Characterisation of the presumed most infectious PTB case is possible by reference to readily available clinical features and laboratory results.

METHODS

Retrospective cohort study of adult, culture-positive PTB cases (151 smear-positive; 162 smear-negative) diagnosed between 1 January 2013 and 30 April 2017 in Canada. We describe cases according to demographic, clinical and laboratory features. We use multivariable multinomial logistic regression to estimate the relative risk ratio (RRR) with 95% CI of features associated with an outcome of smear-positive PTB, characterised by 'typical' chest radiograph findings.

RESULTS

Being Canadian-born, symptomatic, having a subacute duration of symptoms and broad-spectrum antibiotic prescriptions were all more commonly associated with smear-positive than smear-negative disease (36% vs 20%; 95% vs 63%; 88% vs 54%; and 59% vs 28%, respectively). After combining smear status and radiographic features, we show that smear-positive patients with typical chest radiographs were younger, had a longer duration of symptoms (RRR 2.41; 95% CI 1.01 to 5.74 and 2.93; 95% CI 1.20 to 7.11, respectively) and were less likely to be foreign-born, or have a moderate to high-risk factor for reactivation (RRR 0.40; 95% CI 0.17 to 0.92 and 0.18; 95% CI 0.04 to 0.71, respectively) compared with smear-negative patients with atypical chest radiograph findings.

CONCLUSION

A clear picture of the presumed most infectious PTB case emerges from available historical and laboratory information; vigilance for this presentation by front-line providers will support elimination strategies aimed at reducing transmission.

Resource implications of the latent tuberculosis cascade of care: a time and motion study in five countries

BACKGROUND

The End TB Strategy calls for global scale-up of preventive treatment for latent tuberculosis infection (LTBI), but little information is available about the associated human resource requirements. Our study aimed to quantify the healthcare worker (HCW) time needed to perform the tasks associated with each step along the LTBI cascade of care for household contacts of TB patients.

METHODS

We conducted a time and motion (TAM) study between January 2018 and March 2019, in which consenting HCWs were observed throughout a typical workday. The precise time spent was recorded in pre-specified categories of work activities for each step along the cascade. A linear mixed model was fit to estimate the time at each step.

RESULTS

A total of 173 HCWs in Benin, Canada, Ghana, Indonesia, and Vietnam participated. The greatest amount of time was spent for the medical evaluation (median: 11 min; IQR: 6-16), while the least time was spent on reading a tuberculin skin test (TST) (median: 4 min; IQR: 2-9). The greatest variability was seen in the time spent for each medical evaluation, while TST placement and reading showed the least variability. The total time required to complete all steps along the LTBI cascade, from identification of household contacts (HHC) through to treatment initiation ranged from 1.8 h per index TB patient in Vietnam to 5.2 h in Ghana.

CONCLUSIONS

Our findings suggest that the time requirements are very modest to perform each step in the latent TB cascade of care, but to achieve full identification and management of all household contacts will require additional human resources in many settings.

Two Row Wampum, Human Rights, and the Elimination of Tuberculosis from High-Incidence Indigenous Communities

The Two Row Wampum belt is a symbolic record of the first agreement between Europeans and American Indians on Turtle Island (North America). The agreement outlined a commitment to friendship and peace between people living perpetually in parallel, with each party recognizing the other as an equal partner. Subsequent treaty relationships between the Indigenous peoples of the Canadian prairies and settler society, along with the colonially imposed structures they spawned, are widely regarded as having broken the Covenant Chain, the foundation of which is Two Row Wampum. For example, the universal right to health, especially public health, as protected by provincial and territorial legislation in Canada, is under threat in Indigenous communities with a high incidence of tuberculosis. The rights of Indigenous peoples have been asserted, and reasserted, in the United Nations Declaration on the Rights of Indigenous Peoples, the Truth and Reconciliation Commission of Canada, the International Patients' Charter for Tuberculosis Care, and Jordan's Principle. Herein we describe the implementation of a strategic plan that reinforces human rights and dignity in the spirit of Two Row Wampum in contemporary tuberculosis elimination efforts.

Enhancing the public health impact of latent tuberculosis infection diagnosis and treatment (ACT4): protocol for a cluster randomised trial

INTRODUCTION

Treatment of latent tuberculosis (TB) infection (LTBI) is an important component of the End-TB strategy. However, the number of individuals who successfully complete LTBI treatment remains low as there are losses at all steps in the LTBI 'cascade-of-care'. The reasons for these losses are variable and highly dependent on the setting. We have planned a trial of a standardised public health approach to strengthen the management of household contacts (HHCs) of newly diagnosed patients with pulmonary TB. Assessing costs related to approach is a secondary objective of the study.

METHODS AND ANALYSIS

A cluster randomised trial will be conducted in 24 randomisation units (health facilities or groups of health facilities) in five countries. In Phase 1, at intervention sites, we will conduct a standardised assessment of the current LTBI programme, with a focus on cascade-of-care endpoints. Standardised open-ended questionnaires on practices, knowledge, attitudes and beliefs regarding TB prevention are then administered to key patient groups and healthcare workers. At each site, local stake-holders will review study findings and select solutions based on their acceptability, cost and effectiveness. In Phase 2, intervention clinics will implement the selected solutions, along with contact measurement registries and regular in-service LTBI management training. Control sites will continue their usual LTBI care with no explicit evaluation, strengthening or training activities. The primary study outcome is the number of HHC initiating LTBI treatment per newly diagnosed active TB patient, within 3 months of diagnosis of the index patient. An intention-to-treat analysis will be performed, using a Poisson regression approach.

ETHICS AND DISSEMINATION

Ethics approval from the MUHC ethical review board (ERB) was obtained in November 2015. During the study standardised tools will be developed and made publicly available. Key study findings and novel methodologic contributions will be detailed in publications and other dissemination activities.

TRIAL REGISTRATION NUMBER

NCT02810678; Pre-Results.

Is there a fundamental flaw in Canada's post-arrival immigrant surveillance system for tuberculosis?

Background

New immigrants to Canada with a history of tuberculosis or evidence of old healed tuberculosis on chest radiograph are referred to public health authorities for medical surveillance. This ostensible public health protection measure identifies a subgroup of patients (referrals) who are at very low risk (compared to non-referrals) of transmission.

Methods

To assess whether earlier diagnosis or a different phenotypic expression of disease explains this difference, we systematically reconstructed the immigration and transmission histories from a well-defined cohort of recently-arrived referral and non-referral pulmonary tuberculosis cases in Canada. Incident case chest radiographs in all cases and sequential past radiographs in referrals were re-read by three experts. Change in disease severity from pre-immigration radiograph to incident radiograph was the primary, and transmission of tuberculosis, the secondary, outcome.

Results

There were 174 cohort cases; 61 (35.1%) referrals and 113 (64.9%) non-referrals. Compared to non-referrals, referrals were less likely to be symptomatic (26% vs. 80%), smear-positive (15% vs. 50%), or to have cavitation (0% vs. 35%) or extensive disease (15% vs. 59%) on chest radiograph. After adjustment for referral status, time between films, country-of-birth, age and co-morbidities, referrals were less likely to have substantial changes on chest radiograph; OR 0.058 (95% CI 0.018–0.199). All secondary cases and 82% of tuberculin skin test conversions occurred in contacts of non-referrals.

Conclusions

Phenotypically different disease, and not earlier diagnosis, explains the difference in transmission risk between referrals and non-referrals. Screening, and treating high-risk non-referrals for latent tuberculosis is necessary to eliminate tuberculosis in Canada.

Characterization of cytoplasmic viscosity of hundreds of single tumour cells based on micropipette aspiration

Cytoplasmic viscosity (μ c) is a key biomechanical parameter for evaluating the status of cellular cytoskeletons. Previous studies focused on white blood cells, but the data of cytoplasmic viscosity for tumour cells were missing. Tumour cells (H1299, A549 and drug-treated H1299 with compromised cytoskeletons) were aspirated continuously through a micropipette at a pressure of -10 or -5 kPa where aspiration lengths as a function of time were obtained and translated to cytoplasmic viscosity based on a theoretical Newtonian fluid model. Quartile coefficients of dispersion were quantified to evaluate the distributions of cytoplasmic viscosity within the same cell type while neural network-based pattern recognitions were used to classify different cell types based on cytoplasmic viscosity. The single-cell cytoplasmic viscosity with three quartiles and the quartile coefficient of dispersion were quantified as 16.7 Pa s, 42.1 Pa s, 110.3 Pa s and 74% for H1299 cells at -10 kPa (n cell = 652); 144.8 Pa s, 489.8 Pa s, 1390.7 Pa s, and 81% for A549 cells at -10 kPa (n cell = 785); 7.1 Pa s, 13.7 Pa s, 31.5 Pa s, and 63% for CD-treated H1299 cells at -10 kPa (n cell = 651); and 16.9 Pa s, 48.2 Pa s, 150.2 Pa s, and 80% for H1299 cells at -5 kPa (n cell = 600), respectively. Neural network-based pattern recognition produced successful classification rates of 76.7% for H1299 versus A549, 67.0% for H1299 versus drug-treated H1299 and 50.3% for H1299 at -5 and -10 kPa. Variations of cytoplasmic viscosity were observed within the same cell type and among different cell types, suggesting the potential role of cytoplasmic viscosity in cell status evaluation and cell type classification.

Walking between the Lines: Nonvisual Cues for Maintaining Headings during Street Crossings

Five cues were evaluated with respect to their usefulness in directing the headings of pedestrians who were blind during street crossings. The study was conducted at a simulated crosswalk, with the angle of the crosswalk varied relative to the approach and direction of the slope of the ramp. Three cues worked well over the distance equivalent to the width of a six-lane road.

Nonvisual Cues for Aligning to Cross Streets

Accurately aligning to a crosswalk is an important component of safe street crossing for pedestrians who are blind. Six alignment cues were evaluated in a simulated crosswalk environment in which the angle of the crosswalk was not always in line with the slope of the ramp. The effectiveness of each cue is reported and implications are discussed.

‘Bridging the Continuum' - Reporting Population-Level Trends Across the Continuum of Care: The Australian National Cancer Control Indicator (NCCI) Web Site

Background: High-quality data can assist the development of policy and cancer strategies, stimulate lines of research, and inform the provision of care leading to better cancer outcomes. In November 2017 Cancer Australia launched the National Cancer Control Indicators (NCCI) Web site ( https://ncci.canceraustralia.gov.au ), Australia's first interactive Web site of cancer-specific, national population-based data across the continuum of care. The NCCI Web site presents a set of indicators for monitoring national cancer trends and benchmarking internationally across seven key aspects of cancer control; prevention, screening, diagnosis, treatment, psychosocial care, research and outcomes. Aim: By presenting a set of indicators using seven domains from the cancer care continuum, the NCCI Web site presents the most current Australian national data for a range of cancer control indicators in an accessible and interactive format. The primary aim of the NCCI Web site (hosted as part of the Cancer Australia Web site) is to monitor and report the most recent population-level trends to drive improvements across the cancer control continuum in Australia, and to facilitate international benchmarking of Australia's cancer control efforts. Methods: National data level on 33 individual measures across the seven cancer continuum domains was accessed from both government and nongovernment data custodians. Where applicable and available for measures, data were disaggregated and presented by age, sex, indigenous status, remoteness area of residence and socioeconomic status. Review of the data analysis was undertaken by 46 external reviewers including data custodians and subject matter experts. Results: Example summary data from several indicators across the NCCI Web site, including demographic disaggregation by age, sex, remoteness area of residence and socioeconomic status (where available) will be provided. e.g., • Smoking prevalence has decreased substantially over the past 30 years, and smoking rates among both adolescents and adults in Australia are among the lowest in the world. • Cancer mortality rates have been falling steadily since 1995, across most cancer types. Australia has lower mortality rates from cancer when compared with most other similar developed countries, about 6% lower than the estimated global average in 2012. National population-level data showing incidence by stage at diagnosis for the top five most common cancers has also been reported on the Web site - making Australia one of the few countries in the world where these data are available. Conclusion: The NCCI Web site is a flagship data Web site providing, for the first time, an evolving high-level national data resource to monitor Australian population-level trends in cancer control across the continuum. As one of the very few cross-continuum cancer reporting resources in the world, this is a valuable resource for use by those within the international cancer control community.

Collection and Reporting of National Cancer Stage at Diagnosis Data in Australia (STaR Project)

Background: Stage at diagnosis is an important prognostic factor for cancer, providing contextual information for interpreting population health indicators such as mortality from cancer and cancer survival. Australian population-based cancer registries (PBCRs) routinely collect information on cancer incidence and mortality. The need for high quality, comprehensive national data on stage at diagnosis to supplement these data are widely recognized in Australia. The collection and dissemination of quality national stage data will enhance the: • ability to better monitor cancer outcomes, inform cancer control policy; • understand variations across different populations; and • identify where further research and targeted strategies may be required to improve cancer outcomes. Linking data on cancer stage at diagnosis with other administrative cancer data will also allow for a better understanding of the relationship between stage at diagnosis, treatments received, patterns of cancer recurrence, and survival outcomes. Aim: To strengthen national data capacity by collecting and reporting cancer stage at diagnosis for Cancer Australia's Stage, Treatment and Recurrence (STaR) project. Methods: Working with state and territory population-based cancer registries (PBCRs) and the Australian Pediatric Cancer Registry, Cancer Australia supported the development and testing of Business Rules for the collection of national cancer stage at diagnosis for: • The top 5 incident cancers based on the Tumor, Node, and Metastasis (TNM) staging system. These rules were endorsed by the Australasian Association of Cancer Registries (AACR) as a national standard in May 2016; and • Childhood cancers, with a separate set of Business Rules for 16 childhood cancer types based on the Toronto Pediatric Cancer Stage Guidelines. These rules were supported by the AACR as a national standard. Results: Using the AACR-endorsed Business Rules, comprehensive national cancer stage at diagnosis data for the top 5 incident cancers (for 2011) have been collected in Australia for the first time. Over 90% of incidence cases were able to be assigned a value for registry-derived (RD) stage at diagnosis for melanoma (97%), prostate (97%), and female breast (94%) cancers. Lower staging completeness was found for colorectal cancers (88%), and for lung cancers (72%). Business Rules for the collection of stage at diagnosis data for pediatric cancers have also been developed; 93% of sample cases diagnosed in the period 2006-2010 were able to be staged, ranging from 84% for nonrhabdomyosarcoma to 100% for hepatoblastoma. Conclusion: The Business Rules enabled the uniform collection of cancer stage at diagnosis data for the first time in Australia. The collection of these data will allow for the linkage of stage at diagnosis to other sources of information, including patterns of treatments applied, and enable reporting of survival and recurrence outcomes by stage.

Collection and Reporting of System-Wide Cancer Treatment Activity Data As Part of the Stage, Treatment and Recurrence (STaR) Project

Background: The need for high quality, comprehensive national data on the treatments applied to cancers is widely recognized within the Australian cancer control community. The analysis and reporting of cancer treatment data will greatly enhance our ability to better understand cancer care activity and outcomes - and in particular the treatments being applied across population groups. Aim: To collect and report national data on cancer treatments, as part of Cancer Australia's Stage, Treatment and Recurrence (STaR) project. The linking of this data with national data on stage at diagnosis, survival and recurrence, will help inform policy and practice and ultimately improve cancer outcomes. Methods: Cancer Australia developed a dataset of selected surgical procedures for the treatment of the top five incidence cancers (prostate, breast, colorectal, lung, and melanoma). A dataset of key selected radiotherapy, and systemic therapies for the treatment of all cancer types was also developed.

Data for reporting system-wide treatment activity were extracted from existing national health administrative datasets, including: the Pharmaceutical Benefits Scheme (PBS), the Medicare Benefits Schedule (MBS) and the National Hospital Morbidity Database (NHMD). The scope of the analysis was selected surgical procedures, radiotherapy procedures, or pharmaceutical agents administered with the general intent to change the outcome of the cancer and/or provide symptom relief/ palliative care. Results: The data reported provide a high-level national system-wide overview of cancer treatments applied, including: • More than 1 million radiotherapy services were provided for all cancers combined in Australia (as indicated by MBS reimbursement claims data) for the years 2013 to 2015 inclusive; • The number of people receiving systemic anticancer therapies in Australia for all cancers combined (as indicated by PBS reimbursement claims data) increased from 198,756 in 2012 to 247,939 in 2016; and • The number of hospital separations recorded in the NHMD (i.e., episodes of admitted patient care) for patients with a principal diagnosis of cancer undergoing surgery for the treatment of the top five high incidence cancers in Australia increased from 53,516 in 2010 to 57,651 in 2015. Conclusion: National cancer treatment data were successfully collected and reported. Australia is one of very few countries in the world to collect and report national system-wide treatment data with a specific focus on cancer. These data will be linked to cancer incidence, stage at diagnosis, survival and recurrence data to help inform for population-level reporting of cancer outcomes.

Epidemiological and genomic determinants of tuberculosis outbreaks in First Nations communities in Canada

BACKGROUND

In Canada, tuberculosis disproportionately affects foreign-born and First Nations populations. Within First Nations' peoples, a high proportion of cases occur in association with outbreaks. Tuberculosis transmission in the context of outbreaks is thought to result from the convergence of several factors including characteristics of the cases, contacts, the environment, and the pathogen.

METHODS

We examined the epidemiological and genomic determinants of two well-characterized tuberculosis outbreaks attributed to two super-spreaders among First Nations in the province of Alberta. These outbreaks were associated with two distinct DNA fingerprints (restriction fragment-length polymorphisms or RFLPs 0.0142 and 0.0728). We compared outbreak isolates with endemic isolates not spatio-temporarily linked to outbreak cases. We extracted epidemiological variables pertaining to tuberculosis cases and contacts from individual public health records and the provincial tuberculosis registry. We conducted group analyses using parametric and non-parametric statistical tests. We carried out whole-genome sequencing and bioinformatic analysis using validated protocols.

RESULTS

We observed differences between outbreak and endemic groups in the mean number of total and child-aged contacts and the number of contacts with new positive and converted tuberculin skin tests in all group comparisons (p < 0.05). Differences were also detected in the proportion of cases with cavitation on a chest radiograph and the mean number of close contacts in selected group comparisons (p < 0.02). A phylogenetic network analysis of whole-genome sequencing data indicated that most outbreak and endemic strains were closely related to the source case for the 0.0142 fingerprint. For the 0.0728 fingerprint, the source case haplotype was circulating among endemic cases prior to the outbreak. Genetic and temporal distances were not correlated for either RFLP 0.0142 (r² = - 0.05) or RFLP 0.0728 (r² = 0.09) when all isolates were analyzed.

CONCLUSIONS

We found no evidence that endemic strains acquired mutations resulting in their emergence in outbreak form. We conclude that the propagation of these outbreaks was likely driven by the combination of characteristics of the source cases, contacts, and the environment. The role of whole-genome sequencing in understanding mycobacterial evolution and in assisting public health authorities in conducting contact investigations and managing outbreaks is important and expected to grow in the future.

Four Months of Rifampin or Nine Months of Isoniazid for Latent Tuberculosis in Adults

BACKGROUND

A 9-month regimen of isoniazid can prevent active tuberculosis in persons with latent tuberculosis infection. However, the regimen has been associated with poor adherence rates and with toxic effects.

METHODS

In an open-label trial conducted in nine countries, we randomly assigned adults with latent tuberculosis infection to receive treatment with a 4-month regimen of rifampin or a 9-month regimen of isoniazid for the prevention of confirmed active tuberculosis within 28 months after randomization. Noninferiority and potential superiority were assessed. Secondary outcomes included clinically diagnosed active tuberculosis, adverse events of grades 3 to 5, and completion of the treatment regimen. Outcomes were adjudicated by independent review panels.

RESULTS

Among the 3443 patients in the rifampin group, confirmed active tuberculosis developed in 4 and clinically diagnosed active tuberculosis developed in 4 during 7732 person-years of follow-up, as compared with 4 and 5 patients, respectively, among 3416 patients in the isoniazid group during 7652 person-years of follow-up. The rate differences (rifampin minus isoniazid) were less than 0.01 cases per 100 person-years (95% confidence interval [CI], -0.14 to 0.16) for confirmed active tuberculosis and less than 0.01 cases per 100 person-years (95% CI, -0.23 to 0.22) for confirmed or clinically diagnosed tuberculosis. The upper boundaries of the 95% confidence interval for the rate differences of the confirmed cases and for the confirmed or clinically diagnosed cases of tuberculosis were less than the prespecified noninferiority margin of 0.75 percentage points in cumulative incidence; the rifampin regimen was not superior to the isoniazid regimen. The difference in the treatment-completion rates was 15.1 percentage points (95% CI, 12.7 to 17.4). The rate differences for adverse events of grade 3 to 5 occurring within 146 days (120% of the 4-month planned duration of the rifampin regimen) were -1.1 percentage points (95% CI, -1.9 to -0.4) for all events and -1.2 percentage points (95% CI, -1.7 to -0.7) for hepatotoxic events.

CONCLUSIONS

The 4-month regimen of rifampin was not inferior to the 9-month regimen of isoniazid for the prevention of active tuberculosis and was associated with a higher rate of treatment completion and better safety. (Funded by the Canadian Institutes of Health Research and the Australian National Health and Medical Research Council; ClinicalTrials.gov number, NCT00931736 .).

Safety and Side Effects of Rifampin versus Isoniazid in Children

BACKGROUND

The treatment of latent infection with Mycobacterium tuberculosis is important in children because of their vulnerability to life-threatening forms of tuberculosis disease. The current standard treatment - 9 months of isoniazid - has been associated with poor adherence and toxic effects, which have hampered the effectiveness of the drug. In adults, treatment with 4 months of rifampin has been shown to be safer and to have higher completion rates than 9 months of isoniazid.

METHODS

In this multicenter, open-label trial, we randomly assigned 844 children (<18 years of age) with latent M. tuberculosis infection to receive either 4 months of rifampin or 9 months of isoniazid. The primary outcome was adverse events of grade 1 to 5 that resulted in the permanent discontinuation of a trial drug. Secondary outcomes were treatment adherence, side-effect profile, and efficacy. Independent review panels whose members were unaware of trial-group assignments adjudicated all adverse events and progression to active tuberculosis.

RESULTS

Of the children who underwent randomization, 829 were eligible for inclusion in the modified intention-to-treat analysis. A total of 360 of 422 children (85.3%) in the rifampin group completed per-protocol therapy, as compared with 311 of 407 (76.4%) in the isoniazid group (adjusted difference in the rates of treatment completion, 13.4 percentage points; 95% confidence interval [CI], 7.5 to 19.3). There were no significant between-group differences in the rates of adverse events, with fewer than 5% of the children in the combined groups with grade 1 or 2 adverse events that were deemed to be possibly related to a trial drug. Active tuberculosis, including 1 case with resistance to isoniazid, was diagnosed in 2 children in the isoniazid group during 542 person-years of follow-up, as compared with no cases in the rifampin group during 562 person-years (rate difference, -0.37 cases per 100 person-years; 95% CI, -0.88 to 0.14).

CONCLUSIONS

Among children under the age of 18 years, treatment with 4 months of rifampin had similar rates of safety and efficacy but a better rate of adherence than 9 months of treatment with isoniazid. (Funded by the Canadian Institutes of Health Research and Conselho Nacional de Pesquisa; ClinicalTrials.gov number, NCT00170209 .).

Would program performance indicators and a nationally coordinated response accelerate the elimination of tuberculosis in Canada?

Twenty years ago, a National Consensus Conference on Tuberculosis (TB) recommended that the provinces and territories of Canada jointly declare a commitment to TB elimination with national coordination and assured funding, executed by a committee of federal and provincial/territorial representatives. Canada has committed to the global TB elimination targets set forth by the World Health Organization but lacks a coordinated response. In particular, with the exception of one published and implemented by Indigenous Services Canada, there has been no national monitoring and performance framework. Herein, we provide a commentary on the importance, to TB elimination in Canada, of developing such a framework. We invite a debate about whether more can and should be done to monitor and report for action at every jurisdictional level. Of utmost importance will be the need to achieve consensus from stakeholders about what is measured, among whom, how often, who collects and processes data, and how to respond to the successes and failures those data indicate. Insofar, as performance targets are well defined and implemented, national progress towards tuberculosis elimination should accelerate.

Towards the elimination of paediatric tuberculosis in high-income, immigrant-receiving countries: a 25-year conventional and molecular epidemiological case study

The epidemiology of tuberculosis (TB) in high-income countries is increasingly dictated by immigration. The influence of this trend on paediatric TB and TB elimination are not well defined.

We undertook a 25-year conventional and molecular epidemiologic study of paediatric TB in Alberta, one of four major immigrant-receiving provinces in Canada. All isolates of Mycobacterium tuberculosis were DNA fingerprinted using standard methodology.

Between 1990 and 2014, 176 children aged 0–14 years were diagnosed with TB. Foreign-born children or Canadian-born children of foreign-born parents accounted for an increasingly large proportion of total cases during the study period (from 32.1% to 89.5%). Of the 78 culture-positive cases, 35 (44.9%) had a putative source case identified by conventional epidemiology, with 34 (97.1%) having a concordant molecular profile. Of the remaining 43 culture-positive cases, molecular profiling identified spatially and temporally related sources in six cases (14.0%). These six children, along with four other children whose source cases were discovered through reverse-contact tracing, had a high morbidity and mortality.

The increasing burden of paediatric TB in both foreign-born children and Canadian-born children of foreign-born parents calls for more timely diagnosis of source cases and more targeted screening for latent TB infection.

Conventional and molecular epidemiology can inform paediatric TB elimination strategy in high-income countrieshttp://ow.ly/mwbn30iY1WF

Predicting pulmonary tuberculosis in immigrants: a retrospective cohort study

Our objective was to investigate whether pulmonary tuberculosis (PTB) can be predicted from features of a targeted medical history and basic laboratory investigations in immigrants.

A retrospective cohort of 391 foreign-born adults referred to the Edmonton Tuberculosis Clinic (Edmonton, AB, Canada) was studied using multiple logistic regression analysis to predict PTB. Seven characteristics of disease were used as explanatory variables. Cross-validation assessed performance. Each predictor was tested on two outcomes: “culture-positive” and “smear-positive”. Receiver operating characteristic (ROC) curves were generated and the area under the ROC curve (AUC) was quantified.

Symptoms, subacute duration of symptoms, risk factors for reactivation of latent TB infection and anaemia were all associated with a positive culture (adjusted OR 1.79, 2.24, 1.72 and 2.28, respectively; p<0.05). Symptoms, inappropriate prescription of broad-spectrum antibiotics and a “typical” chest radiograph were associated with smear-positive PTB (adjusted OR 2.91, 1.55 and 12.34, respectively; p<0.05). ROC curve analysis was used to test each model, yielding AUC=0.91 for the outcome “culture-positive” disease and AUC=0.94 for the outcome “smear-positive” disease.

PTB among the foreign-born can be predicted from a targeted medical history and basic laboratory investigations, raising the threshold of suspicion in settings where the disease is relatively rare.

In high-income, low tuberculosis incidence countries, certain clinical characteristics should raise the threshold of suspicion to confirm a timely diagnosishttp://ow.ly/bRDZ30iPurz

Determinants of tuberculosis trends in six Indigenous populations of the USA, Canada, and Greenland from 1960 to 2014: a population-based study

BACKGROUND

Tuberculosis continues to disproportionately affect many Indigenous populations in the USA, Canada, and Greenland. We aimed to investigate whether population-based tuberculosis-specific interventions or changes in general health and socioeconomic indicators, or a combination of these factors, were associated with changes in tuberculosis incidence in these Indigenous populations.

METHODS

For this population-based study we examined annual tuberculosis notification rates between 1960 and 2014 in six Indigenous populations of the USA, Canada, and Greenland (Inuit [Greenland], American Indian and Alaska Native [Alaska, USA], First Nations [Alberta, Canada], Cree of Eeyou Istchee [Quebec, Canada], Inuit of Nunavik [Quebec, Canada], and Inuit of Nunavut [Canada]), as well as the general population of Canada. We used mixed-model linear regression to estimate the association of these rates with population-wide interventions of bacillus Calmette-Guérin (BCG) vaccination of infants, radiographic screening, or testing and treatment for latent tuberculosis infection (LTBI), and with other health and socioeconomic indicators including life expectancy, infant mortality, diabetes, obesity, smoking, alcohol use, crowded housing, employment, education, and health expenditures.

FINDINGS

Tuberculosis notification rates declined rapidly in all six Indigenous populations between 1960 and 1980, with continued decline in Indigenous populations in Alberta, Alaska, and Eeyou Istchee thereafter but recrudescence in Inuit populations of Nunavut, Nunavik, and Greenland. Annual percentage reductions in tuberculosis incidence were significantly associated with two tuberculosis control interventions, relative to no intervention, and after adjustment for infant mortality and smoking: BCG vaccination (-11%, 95% CI -6 to -17) and LTBI screening and treatment (-10%, -3 to -18). Adjusted associations were not significant for chest radiographic screening (-1%, 95% CI -7 to 5). Declining tuberculosis notification rates were significantly associated with increased life expectancy (-37·8 [95% CI -41·7 to -33·9] fewer cases per 100 000 for each 1-year increase) and decreased infant mortality (-9·0 [-9·5 to -8·6] fewer cases per 100 000 for each death averted per 1000 livebirths) in all six Indigenous populations, but no significant associations were observed for other health and socioeconomic indicators examined.

INTERPRETATION

Population-based BCG vaccination of infants and LTBI screening and treatment were associated with significant decreases in tuberculosis notification rates in these Indigenous populations. These interventions should be reinforced in populations still affected by tuberculosis, while also addressing the persistent health and socioeconomic disparities.

FUNDING

Public Health Department of the Cree Board of Health and Social Services of James Bay.