A PNAS study co-authored by SFI Science Board co-chair Marcus Feldman helps explain why outbreaks of tuberculosis broke out after French Canadian fur traders stopped trading with indigenous peoples of western Canada.
The Stanford researchers tracked a particular strain of TB that was unintentionally passed from French Canadian voyagers to indigenous peoples during a 150 year period of fur trade from about 1710 to 1870.
Tuberculosis often lies dormant in a human host for decades and apparently did so in many indigenous western Canadians exposed to TB during the active fur trade era.
According the Stanford study, it took a shift in the environment -- in this case, confinement to reservations and consequent population density, malnutrition, and poor health conditions -- to create the conditions conducive to outbreaks.
"Up to now, it has been relatively hard to define the locations of origin of a strain of tuberculosis more precisely than a continent," says Feldman.
By looking at large numbers of bacterial samples and integrating genetic analysis with the work of fur trade historians, the researchers gained insight into how this particular strain must have spread.
Read the PNAS paper (April 4, 2011)
Read the Stanford Report article (April 7, 2011)