Using both whole-genome sequencing and social-network analysis, researchers led by Patrick Tang at the British Columbia Centre for Disease Control report that increased crack cocaine use likely led to the tuberculosis outbreak in British Columbia in 2006 and 2007. As they described in their New England Journal of Medicine article, the researchers sequenced 32 Mycobacterium tuberculosis isolates from the outbreak and 4 historical isolates while also carrying out an epidemiological investigation of the patients that included a social-network questionnaire in addition to traditional contact tracing. "The simultaneous reappearance of two extant lineages suggests that a social or environmental factor, not a genetic change in the organism, most likely triggered the outbreak," the authors write. "Our observations suggest that a rise in crack cocaine use within the community, peaking in 2006, may have been this trigger." In MIT's Technology Review, Harvard School of Public Health's Joel Miller adds that the study indicates "that it is feasible to combine genetic data and social structure to give an idea of the transmission chain and to distinguish two outbreaks going on at the same time."
Social Networks and Genomics
Feb 24, 2011