Researchers have found that a strain of tuberculosis (TB) responsible for devastating some isolated Aboriginal populations in Canada was first introduced to these communities by French Canadian fur traders between 1710 and 1870.

The team has found a traceable link between the fur trade routes and modern day patterns of tuberculosis. Wendy Wobeser, a professor with Queen’s Division of Infectious Diseases, is the member of this research team who originally identified the presence of this particular strain of TB in remote Aboriginal communities in Saskatchewan. Through her later work in northwestern Ontario with the Sioux Lookout First Nations Health Authority the link was made to the mode of introduction of the strain to remote First Nations communities.

“This research represents a level of thinking never applied to tuberculosis epidemiology in this country or elsewhere,” says Dr. Wobeser. “Examining the migration and epidemiological traits of this disease could help researchers explain why it is proving so difficult to eradicate.”

The researchers have hypothesized that social distance between indigenous peoples and various migrant groups contributed to this historical phenomenon. While the fur trade era was characterized by close social contact, intermarriage and trading collaborations, later waves of migrants who moved across Canada remained more socially and geographically isolated from indigenous peoples.

In order to better understand the migratory dynamics of TB in Canada, the researchers focused on a particular bacterial lineage. They connected the dispersal of this particular strain of TB to an estimated 5,419 individuals who migrated across Canada from Quebec during the fur trade era.

Despite the fact that later waves of immigration brought millions of individuals to Canada from global regions of high TB incidence, the particular tubercular strain introduced by the early fur traders remains the dominant strain in Western indigenous communities and among modern-day French-Canadian populations in Quebec.

By the late 19th century, indigenous populations were often forcibly segregated from the non-Aboriginal population, beginning the trend of displacement, crowding, and institutionalization that contributed to subsequent devastating TB epidemics among indigenous populations in Canada.

This research was published recently in the Proceedings of the National Academy of Sciences.