Whole-Genome Sequencing and Social-Network Analysis of a Tuberculosis Outbreak

An outbreak of tuberculosis occurred over a 3-year period in a medium-size community in British Columbia, Canada. The results of mycobacterial interspersed repetitive unit–variable-number tandem-repeat (MIRU-VNTR) genotyping suggested the outbreak was clonal. Traditional contact tracing did not identify a source. We used whole-genome sequencing and social-network analysis in an effort to describe the outbreak dynamics at a higher resolution. Mycobacterium tuberculosis is an important infectious disease even in developed countries with extensive control programs. This is the case in British Columbia, Canada, where the 2007 incidence rate of 6.4 cases per 100,000 population exceeded the national average of 4.7 cases per 100,000 population. 1 In May 2006, a case of smear-negative pleural tuberculosis was diagnosed in an adult in a medium-size community in British Columbia. A second case, manifested as disseminated tuberculosis, was reported in an infant in July 2006. Reverse contact tracing identified nine additional cases between August and October 2006, when the British Columbia Centre for Disease Control . . .