Tuberculosis in Canada, 2016.

BACKGROUND: Tuberculosis (TB) is a major global health problem that affected an estimated 10.4 million people worldwide in 2016. The Public Health Agency of Canada (PHAC) monitors active TB disease through a national surveillance system, which is a collaborative effort withthe provinces and territories. OBJECTIVE: This article presents an epidemiological summary of the active TB disease cases reported from 2006 to 2016, with a focus on 2016. Treatment outcomes for cases diagnosed in 2015 are also presented. METHODS: The Canadian Tuberculosis Reporting System (CTBRS) is a case-based surveillance system that maintains non-nominal data on people diagnosed with active TB disease in Canada. Data are collected annually from the provinces and territories, analyzed by PHAC and validated by each province and territory. RESULTS: The number of active TB disease cases increased from 1,642 in 2015 to 1,737 in 2016, corresponding to an increase in incidence rate from 4.6 to 4.8 per 100,000 population. Foreign born individuals continued to make up the majority of cases reported (70%) and the incidence rate remained highest among Canadian born Indigenous people (23.5 per 100,000 population) and was particularly high within the Inuit population (170.1 per 100,000 population). Over the past decade, there was a slight decrease in the number of cases among children and the proportion of re-treatment cases declined from 8.3% of cases in 2006 to 5.4% of cases in 2016. CONCLUSION: Although tuberculosis incidence rates in Canada are low in the global context and have been relatively stable over the last decade, there has been a slight increase in rates over the last three years, especially in the foreign born population which accounts for the majority of cases. The decrease in cases among children suggests less active transmission and the low proportion of re-treatment cases suggests effective treatment and adherence.

Tuberculosis drug resistance in Canada: 2006-2016.

BACKGROUND: Drug-resistant strains of tuberculosis (TB) pose a serious threat to TB prevention and control efforts. The Canadian Tuberculosis Laboratory Surveillance System (CTBLSS) was created in 1998 to monitor emerging trends and patterns in TB drug resistance in Canada. OBJECTIVE: To present a descriptive overview of TB drug resistance data collected through the CTBLSS for the years 2006 to 2016 in Canada, with a focus on 2016. METHODS: The CTBLSS is an isolate-based surveillance system designed to collect data on TB drug resistance across Canada. Each year, data are collected and analyzed by the Public Health Agency of Canada (PHAC) and then validated by the submitting laboratory. RESULTS: In 2016, anti-tuberculosis drug susceptibility test results were reported for 1,452 isolates. The proportion of TB drug-resistant strains remained relatively stable with 108 (7.4%) of the isolates classified as monoresistant, five (0.3%) isolates as polyresistant and 17 (1.2%) as multidrug-resistant TB (MDR-TB) strains. In 2016, there were no extensively drug-resistant TB (XDR-TB) isolates identified. Males accounted for 792 (54.5%) of all reported isolates and 64 (49.2%) of the resistant strains and females accounted for 11 (64.7%) of the MDR-TB strains. Between 2006 and 2016, individuals between 15 and 44 years of age comprised 47.4% of all reported isolates, 54.0% of isolates showing any resistance and 72.3% of MDR-TB strains. CONCLUSION: TB drug resistance levels have been relatively low and stable over the past 11 years and have remained below the global average since national surveillance began. However, with growing worldwide concern about drug resistance and the emergence of XDR-TB, the CTBLSS will remain vital to the monitoring of TB drug resistance in Canada.

Tuberculosis in Canada - Summary 2015.

BACKGROUND: Tuberculosis (TB) is a global health problem that affects an estimated 10 million people each year. In Canada, the Public Health Agency of Canada (PHAC) monitors active TB disease through the Canadian Tuberculosis Reporting System (CTBRS). OBJECTIVE: To report on and analyze the number of new and re-treatment cases of TB cases in Canada reported for 2015. Results are discussed in the context of previous year's data. Treatment outcomes for cases diagnosed in 2014 are also presented. METHODS: The CTBRS is a case-based surveillance system that maintains non-nominal data on active cases of TB. Data are collected and analyzed by PHAC and validated by each province and territory; no statistical tests were used. RESULTS: A total of 1,639 cases of active TB disease were reported in 2015, representing a slight increase from the number of cases reported in 2014 (1,614) and a corresponding increase in the incidence rate from 4.5 per 100,000 to 4.6 per 100,000 population. Although the incidence rate of TB remained highest in Nunavut at 119.2 per 100,000 population in 2015, it was nearly half of what it was in 2014. An outbreak in Newfoundland and Labrador resulted in a notable increase in the number of reported cases and incidence rate in this province. In 2015, males accounted for just over half of the reported cases at 53% and older Canadians carried the highest burden of TB with an incidence rate of 10.3 per 100,000 population. Foreign-born individuals continued to account for the majority of reported cases at 71%, but the incidence rate remained highest among Canadian-born Indigenous people at 17.1 per 100,000 population and in particular within the Inuit population at 166.2 per 100,000. Pulmonary TB remained the most commonly reported site of disease. Treatment outcome data for cases reported in 2014 indicated that 85% of cases had been cured or had completed treatment. CONCLUSION: Tuberculosis rates in Canada have changed little over the last decade and overall, remain stable and low in the global context. However, foreign-born individuals and Indigenous Canadians continued to be disproportionately represented among reported cases of TB in 2015. As the primary source of national data on TB cases, the data within this report provide timely information for public health action, as well as policy and program development and assessment.

A population-based study of tuberculosis case fatality in Canada: do Aboriginal peoples fare less well?

SETTING: The Province of Alberta, Canada. OBJECTIVES: To explore trends in tuberculosis (TB) case fatality, compare TB case-fatality rates by population group and determine prognostic factors associated with TB-related death in Alberta from 1996 to 2012. DESIGN: Retrospective cohort analysis. RESULTS: During the study years, all-cause TB case fatality fell from 10.7% to 6.3%; the fall was attributable to a change in population structure, as there were more foreign-born and fewer older cases with time. A stable 2% of TB cases died without treatment. Compared to other population groups, Canadian-born Aboriginal case patients were more likely to die without treatment and to die younger. Of TB deaths that were TB-related, 68.9% occurred before or during the initial phase of treatment; of these, TB was a contributory cause of death in 77.5%, i.e., another medical condition was the primary cause of death. In multivariate analysis, age >64 years, aboriginality and miliary/disseminated or central nervous system disease were independent predictors for TB-related death. CONCLUSION: Preventive therapy for those with latent tuberculous infection and a high-risk medical condition, early diagnosis of disease, and special support of older, Aboriginal or comorbid cases, once diagnosed, are necessary to further minimise TB case fatality in Alberta, Canada.

A summary of tuberculosis drug resistance in Canada, 2003-2013.

BACKGROUND: Drug-resistant strains of tuberculosis (TB) pose a serious threat to prevention and control efforts. In response to this growing worldwide concern, the Public Health Agency of Canada (PHAC) established and maintains the Canadian Tuberculosis Laboratory Surveillance System (CTBLSS) in partnership with the Canadian Tuberculosis Laboratory Technical Network (CTLTN) and participating laboratories. OBJECTIVE: To report on national trends and patterns in anti-tuberculosis drug resistance in Canada for the years 2003 to 2013. METHOD: At the beginning of each calendar year, participating laboratories submit to PHAC reports on the results of anti-tuberculosis drug susceptibility testing for all isolates tested during the preceding year. These data are then analyzed by PHAC and the results are validated by supplying laboratories. The results are published annually as the Tuberculosis Drug Resistance in Canada series. RESULTS: In 2013, anti-tuberculosis drug susceptibility test results for 1,380 isolates were reported to PHAC. Of these, 762 (54%) were reported as Mycobacterium tuberculosis complex (MTBC) where the species was known. Two thirds (68%) of all the reported isolates originated from the three largest provinces, British Columbia, Ontario and Quebec. Overall, of the laboratory results received, 112 (8.1%) showed resistance to at least one first-line drug and, of these, the majority (93 or 83%) were monoresistant. CONCLUSION: TB drug resistance observed in Canada remains well below the global average. Over the last 10 years, the percentage of isolates with resistance to one or more of the first-line medications has decreased from 10.5% in 2003 to 8.1% in 2013.

A summary of tuberculosis in Canada, 2013.

BACKGROUND: The Public Health Agency of Canada (PHAC) monitors active TB disease through the national collaborative Canadian Tuberculosis Reporting System (CTBRS). PHAC uses TB surveillance data and reports to monitor progress towards achieving Canada's goal of preventing and controlling the transmission of TB, as outlined in Tuberculosis Prevention and Control in Canada-A Federal Framework for Action. OBJECTIVE: To provide an overview of the preliminary number of reported active (new and re-treatment) TB cases and corresponding incidence rates in Canada for 2013. METHODS: Provincial and territorial public health authorities voluntarily submit data to the CTBRS on an annual basis for all TB cases that meet the case definition for national-level surveillance. These data are analyzed by PHAC; the results of the analysis are validated by the supplying jurisdiction and are published annually as the Tuberculosis in Canada Pre-release series. RESULTS: In Canada, 1,640 new active and re-treatment TB cases were reported in 2013 for an overall incidence rate of 4.7 per 100,000 population. There was little change from preceding years in the overall distribution of cases by sex and age group. Although individuals aged 25 to 34 years old represented the largest percentage of reported cases (16%), the highest incidence rate was observed for those aged 75 years or older. Incidence rates in British Columbia, Manitoba, Saskatchewan, Nunavut, and Northwest Territories were higher than the Canadian rate, with Nunavut showing the highest incidence rate. Foreign-born individuals continue to account for the majority of reported TB cases, but the incidence rate per 100,000 population remains highest among Canadian-born Aboriginal people. CONCLUSION: Preliminary data from 2013 indicate that there were no notable changes in the number of reported cases of TB or in the overall incidence rate in Canada when compared with previous years' data. Similarly, no changes were noted in the distribution of cases by province or territory, age group or sex.

Tuberculosis in Canada: 1924-2012.

BACKGROUND: Tuberculosis (TB) has been a notifiable disease since 1924 and remains an important and serious global public health challenge. Understanding the patterns and characteristics of TB are key to controlling and preventing further spread of the disease. OBJECTIVE: To provide an overview of national TB surveillance data collected through two national surveillance systems and to highlight important trends in recent years. METHODS: Trends in the incidence of TB since 1924 are presented. Descriptive results from the Canadian Tuberculosis Reporting System (CTBRS) and the Canadian Tuberculosis Laboratory Surveillance System (CTBLSS) are presented, with a focus on the years from 2002 to 2012. No statistical tests of significance were performed. RESULTS: Since the 1940s, both the number of reported TB cases and the overall Canadian incidence rate have declined. Males have always accounted for the greatest percentage of cases overall and individuals between the ages of 25 and 34 have typically accounted for the largest number of reported cases relative to other age groups. From 2002 to 2012, 66% of reported TB cases were foreign-born, but the highest burden of TB was in the Canadian-born Aboriginal population, with an average incidence rate five times that of the overall Canadian rate. Reported drug resistance in Canada remains consistently below international levels. CONCLUSION: Overall, Canada has one of the lowest TB disease rates in the world. However, foreign-born individuals and Aboriginal people continue to be disproportionately represented among cases diagnosed in Canada. Surveillance systems like the CTBRS and CTBLSS are fundamental in providing information needed to target resources where they can be most effective.

The preferred treatment for stage I seminoma: a survey of Canadian radiation oncologists.

AIMS: To evaluate the preferences of radiation oncologists for managing stage I seminoma. MATERIALS AND METHODS: An electronic survey evaluating the management of stage I seminoma patients was sent to Canadian radiation oncologists to determine their treatment recommendations and preferences. RESULTS: The survey completion rate was 74% among eligible respondents (78/105). Most (56%) felt that surveillance was the preferred treatment for patients, whereas 31% thought that adjuvant radiotherapy was best, 1% chose adjuvant chemotherapy as being the preferred option and 12% were unsure. Most would choose the same treatment for themselves if they were diagnosed with stage I seminoma. A previously published survey found that most respondents considered radiotherapy as the best option. CONCLUSIONS: Most Canadian radiation oncologists now favour surveillance for most stage I seminoma patients.

Acetolactate synthase inhibiting herbicides bind to the regulatory site.

Acetolactate synthase from spontaneous mutants of tobacco (Nicotiana tabacum; KS-43 and SK-53) and cotton (Gossypium hirsutum; PS-3, PSH-91, and DO-2) selected in tissue culture for resistance to a triazolopyrimidine sulfonanilide showed varying degrees of insensitivity to feedback inhibitor(s) valine and/or leucine. A similar feature was evident in the enzyme isolated from chlorsulfuron-resistant weed biotypes, Kochia scoparia and Stellaria media. Dual inhibition analyses of triazolopyrimidine sulfonanilide, thifensulfuron, and imazethapyr versus feedback inhibitor leucine revealed that the three herbicides were competitive with the amino acid for binding to acetolactate synthase from wild-type cotton cultures. Acetolactate synthase inhibiting herbicides may bind to the regulatory site on the enzyme.