Tuberculosis Elimination in Canada Back to Basics

Transcription

1 Tuberculosis Elimination in Canada Back to Basics Richard Long, MD University of Alberta The Lung Association: TB Elimination 2016 Toronto, ON, November 15-16, 2016

2 TB Elimination: Back To Basics Financial Interest Disclosure (over the past 24 months) Dr. Richard Long I have no conflict of interest.

3 Definitions: Pre-Elimination: <10 notified TB cases (all forms) per million population and year. To be achieved in Canada by Elimination: <1 notified TB case (all forms) per million population and year. To be achieved in Canada by World Health Organization

4 Tuberculosis in Canada, 2012 (PHAC)

5 Arden House Conference on Tuberculosis, Harriman, New York, 1959 Tuberculosis control has progressed to the point where virtual elimination of the disease as a public health problem appears to be within reach The remarkable progress made against tuberculosis since the advent of chemotherapy has mitigated the fear that used to be felt about the disease. Unfortunately, it has also been accompanied by some complacency and loss of interest in finishing a task that once was considered extremely urgent. Semin Resp Crit Care Med 2004; 25:

6 National TB rate per 100,000 Actual incidence of tuberculosis in Canada , and projected rates based on pre-elimination targets set in 1997 and Actual incidence 1997 Target 2006 Target CMAJ 2015; 187:

7 Cases per 100,000 population Crude Tuberculosis Rate in Canada by Population Group (Three Year Rolling Average) Canadian-Born Aboriginal Foreign-Born 10 5 Canadian-Born Non- Aboriginal Year Can Respir J 2013; 20(4):

8 To get there we must focus on three areas: 1. TB in the Foreign Born 2. TB in Indigenous Peoples (First Nations, Métis and Inuit) 3. Federal Provincial/Territorial Collaboration

9 To get there we must focus on three areas: 1. TB in the Foreign Born

10 Proportion (%) Proportion of New Immigrants to Canada From Europe vs. Asia & Africa Europe Asia & Africa Year Can RespirJ 2015; 22:

11 Number of New Immigrants from High TB Incidence Countries, Per 100,000 Population Canada USA Year World Health Organization; Citizenship and Immigration Canada; Statistics Canada; US Department of Homeland Security; US Census.

12 Proportion of New Immigrants to Canada & the USA from High Incidence Countries of Origin Canada USA

13 Number of Cases Number of US TB Cases Reported in US-Born and Foreign-Born Persons, Unknown Origin US Born Cases Foreign Born Cases * Year

14 Crude Tuberculosis Rates in Canada and the United States, Canada 8 USA National 6 Tuberculosis Rate (per 100,000) Year

15 Age and sex adjusted incidence of pediatric tuberculosis by population group and time period in Alberta,

16 Number of Cases 30 Figure 2: Number of pediatric tuberculosis cases in 5-year periods by population group in Alberta, Year CBO-CB CBO-FB FB RFN

17 How effective is Canada s TB Surveillance Strategy in Identifying Immigrants at Risk of Developing and Transmitting Pulmonary TB? A Population-Based Cohort Study (L. Asadi) Permanent residents, aged years, who arrived in Alberta between ,225 IRCC Referrals Non-Referrals ,657 PTB Cases ( ) PTB Cases ( ) C + PTB 141/ /105 CRUDE RATES 28/10 5 HRC S + PTB 31/ /10 5 HRC

18 % 100 Baseline characteristics of 234 foreign-born culture-positive pulmonary TB patients aged years and diagnosed in Alberta between 2004 and >200 Incidence in Country of Birth Cavitation Smear Positive Referrals Non-referrals

19 Months in Canada before diagnosis of culture-positive pulmonary tuberculosis in 234 foreign-born persons by referral status Medium Mean Months in Canada Referrals Non-referrals

20 Figure 3: Transmission Events (TST Conversions and Secondary Cases) Arising from the 234 Permanent Residents who developed culture-positive PTB ---- represents transmissions to close contacts *secondary cases were not also counted as TST conversions.

21 Smear-negative cases are symptomatic 50% of the time and intermittently excrete small numbers of bacilli. Smear-positive cases develop within the same timeframe as smearnegative cases but are symptomatic 90% of the time and more infectious. Minimal smear-negative disease does not necessarily progress to more advanced smear-positive disease.

22 Referral Non-referral

23 Can J Public Health 2013; 104(1): e22-e27

24 CBO Canadian born other, FBO Foreign-born other, CBA Canadian-born Aboriginal, FBSSA Foreign-born Sub-Saharan-Africa PLoS One (2014) 9 (6): eq8993.doi: /journal.pone

25 We need to be concerned about the conditions of settlement and the circumstances that promote reactivation of LTBI in migrant communities Are we providing support for migrants; are we ensuring their social participation, access to healthcare and rights to freedom from discrimination?

26 1. TB in the foreign-born - considerations Re-institute the long form of the census Work with Immigration, Refugees and Citizenship Canada and Public Health Agency of Canada towards revision of the surveillance referral process Support initiatives aimed at expanded surveillance and targeted treatment of LTBI Support of MDR-TB management capacity in major immigrant-receiving provinces Support migrant integration

27 To get there we must focus on three areas: 2.TB in Indigenous Peoples (First Nations, Métis and Inuit)

28 From the Arden House perspective, the equivocal historical impact of chemotherapy on TB incidence is consistent with two interpretations. One is the belief that endogenous reactivation of old TB infections contributes the majority of morbidity during the decline of an epidemic. If so, curative therapy for TB disease would lessen incident cases only decades later when the reservoir of infection would be nearing depletion without replenishment. Conversely, if recent transmission of MTB infection were contributing to TB incidence more than believed, failure to implement treatment programs for rendering incident cases non-contagious would have diluted chemotherapy s influence on near-term incidence because transmission would continue. Semin Resp Crit Care Med 2004; 25:

29 Tuberc Lung Dis 1993; 74:

30 Can Respir J 2013; 20(4):

31 Highly Infectious Source Case(s) Revised from Am Rev Tuberc 1957; 75:

32 Outbreaks disrupt routine TB control activities and could hinder elimination efforts at the local level if further generations of transmission occur, notably if the prevalence of LTBI has been increased as a result. Outbreaks also unveil pre-existing weaknesses in TB control activities such as absent or insufficient infection control, diagnostic delays or incomplete evaluation and treatment of contacts. Semin Resp Crit Care Med 2004; 25:

33 Each of the 222 true potential TB transmitters diagnosed in 2007 and 2008 had a 30 month transmission window All DNA Fingerprinting was performed by NML using 24 loci MIRU-VNTR 222

34 TB Transmission, Prairie Provinces, Canadian-born Potential TB Transmitters Indigenous 198 (89.2%) 24 Non-Indigenous (10.8%) 1025 or 94.5% of all transmission events (120 secondary cases) 60 or 5.5% of all transmission events (6 secondary cases)

35 Rate per 100,000 persons Rate Ratio TB Incident Rate Ratio: Indigenous vs. Non-Indigenous Canadian-Born Indigenous Rate Non-Indigenous Rate Rate Ratio Year 0

36 In their book, The White Plague, Rene and Jean Dubos warned of the dangers of treating the symptoms of pathology that is disease and ignoring the social factors that produce susceptibility. In the Many Farms community-health experiments on the Navajo Reservation in the 1950s they were disillusioned when they could not put an end to TB or other diseases that were sustained by social circumstance. Members of the Arden House conference were troubled by visions of TB evading [elimination] by aligning itself into social disparities thereby taking advantage of elusive barriers that would interfere with treatment campaigns.

37 NEJM 2015; 373:

38 2. TB in indigenous peoples - considerations Outbreak and high incidence communities Communities becoming an equal partner in TB control Implementing the TB Patients Charter of Tuberculosis Care Early diagnosis; effective case and contact management Expanded programs of prevention an elimination strategy Implementation of the Virtual clinic model to the middle and far North Engage with other Federal departments and agencies to address socioeconomic factors that contribute to TB

39 To get there we must focus on three areas: 3.Federal Provincial/Territorial Collaboration

40 Public Health 1959 Curative treatment of tuberculosis is a public health obligation. Arden House Conference on Tuberculosis 1990 Among basic strategies that are consistently effective for TB elimination: Direct government responsibility for diagnosis, treatment and prevention of tuberculosis (the government is responsible by law for assuring that tuberculosis is identified early and that cure of the patients is achieved). First IUATLD (European Region)/WHO TB Elimination Workshop at Wolfheze, Netherlands

41 (Re-)establishment and/or maintenance of a national tuberculosis network in terms of funding/human resources and facilities is vital Eur Respir J 2002; 19:765-75

42 The Canadian TB Elimination Network PHAC CTBEN FPT- TB Working Group Communicable and Infectious Disease Steering Committee Public Health Network Council Sponsor: National Collaborating Centres for Infectious disease Indigenous health Determinants of health

43 One of the basic elements of the World Health Organization global STOP TB initiative is to monitor and evaluate performance and impact, which is a responsibility of public health agencies working on TB control World Health Organization. Stop TB Partnership. The Stop TB Strategy. WHO 2006.

44 Questions?