To characterize tuberculosis (TB) transmission among the Indigenous and non-Indigenous Canadian-born peoples of the prairie provinces of Canada

Setting The prairie provinces of Canada. Objective To characterize tuberculosis (TB) transmission among the Indigenous and non-Indigenous Canadian-born peoples of the prairie provinces of Canada. Design A prospective epidemiologic study of consecutively diagnosed adult (age ≥ 14 years) Canadian-born culture-positive pulmonary TB cases on the prairies, hereafter termed “potential transmitters,” and the transmission events generated by them. “Transmission events” included new positive tuberculin skin tests (TSTs), TST conversions, and secondary cases among contacts. Results In the years 2007 and 2008, 222 potential transmitters were diagnosed on the prairies. Of these, the vast majority (198; 89.2%) were Indigenous peoples who resided in either an Indigenous community (135; 68.2%) or a major metropolitan area (44; 22.2%). Over the 4.5-year period between July 1 , 2006 and December 31 2010, 1085 transmission events occurred in connection with these potential transmitters. Most of these transmission events were attributable to potential transmitters who identified as Indigenous (94.5%). With a few notable exceptions most transmitters and their infected contacts resided in the same community type. In multivariate models positive smear status and a higher number of close contacts were associated with increased transmission; adjusted odds ratios (ORs) and 95% confidence intervals (CIs), 4.30 [1.88, 9.84] and 2.88 [1.31, 6.34], respectively. Among infected contacts, being Indigenous was associated with disease progression; OR and 95% CI, 3.59 [1.27, 10.14] and 6.89 [2.04, 23.25] depending upon Indigenous group, while being an infected casual contact was less likely than being a close contact to be associated with disease progression, 0.66 [0.44, 1.00]. Conclusion In the prairie provinces of Canada and among Canadian-born persons, Indigenous peoples account for the vast majority of cases with the potential to transmit as well as the vast majority of infected contacts. Active case finding and preventative therapy measures need to focus on high-incidence Indigenous communities. Citation: Patel S, Paulsen C, Heffernan C, Saunders D, Sharma M, King M, et al. (2017) Tuberculosis transmission in the Indigenous peoples of the Canadian prairies. PLoS ONE 12(11): e0188189. https://doi.org/10.1371/journal.pone.0188189 Editor: Joan A. Caylà, Agencia de Salut Publica de Barcelona, SPAIN Received: December 15, 2016; Accepted: October 30, 2017; Published: November 14, 2017 Copyright: © 2017 Patel et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: The data in the DTT project is linked across many jurisdictional divides, including Provincial borders, on and off-reserve, communities, and treaties. These data include individual level stories (qualitative data), and individual level TB records collected as part of enhanced surveillance in order to shed light on drivers of TB in the Canadian Prairies. The approvals process for collecting these data is described in the following paper: Boffa J, King M, McMullin K, Long R. A process for the inclusion of Aboriginal people in health research: Lessons from the Determinants of TB Transmission Project. Soc Sci Med 2011;72:733-738. As part of our consultations with community leaders, and our Provincial Network Committees, Published: November 14, 2017 https://doi.org/10.1371/journal.pone.0188189 Tuberculosis transmission in the Indigenous peoples of the Canadian prairies Smit Patel, Catherine Paulsen, Courtney Heffernan, Duncan Saunders, Meenu Sharma, Malcolm King, Vernon Hoeppner, Pamela Orr, Dennis Kunimoto, Dick Menzies, Sara Christianson, Joyce Wolfe, Jody Boffa, Kathleen McMullin, Carmen Lopez-Hille, Ambikaipakan Senthilselvan, Richard Long