Social colonization: primary root cause of TB among aboriginal populations

Elaine Randell (Communicable Disease Consultant, Department of Health and Social Services, Government of Nunavut, Canadian Public Health Association) presented evidence at the Senate hearing on Health in April 2010. She argued that,

“To fully understand the pattern of TB in most aboriginal populations in Canada, it’s important for us to understand the history of TB among this group, where the epidemic came from, as well as the social determinants of health that significantly contribute to the continuing high rates of infection and disease.

Contact with European merchants and traders in Canada occurred in sequence, beginning with the Atlantic provinces in the 16th century, Ontario and Quebec in the 17th century, the Pacific provinces in the 18th century, the prairies in the 19th century, and the territories in the 20th century. Contact in the territories began in the west in Yukon, and to the east, which is now Nunavut. The subsequent wave of settlement that followed this changed the way that aboriginal populations lived, from small, isolated, mobile groups to large groups living in settlements and stationary.

This social colonization was what provided the vector for the spread of tuberculosis. The earlier the epidemic began, the sooner it reached its peak and began to fall, until the last 15 years or so, as we’ve heard, which is why we see the pattern of TB rates we have amongst aboriginal populations, the rates being lowest amongst the population where the social colonization occurred earliest and highest in areas such as Nunavut, where it occurred most recently.

Inadequacies in the social determinants of health are key in continuing the cycle of outbreaks and high rates of TB among aboriginal populations. Crowded and inadequately ventilated housing increases transmission. I’m aware of situations in which infectious cases have been recorded in houses with 13 people or more, including young children, who are especially vulnerable. The rate of transmission in these situations is very high. Those without housing move from home to home as guests, thus increasing the number of people who are exposed and infected. Long periods of cold weather and darkness in the north lead to longer periods of time spent indoors in crowded and inadequately ventilated housing. This leads to increased exposure and shared air space and subsequent increase in transmission. Poor nutritional status increases risk of progression from infection to disease. In many remote communities, selection of nutritious foods such as fresh vegetables and fruits is extremely limited and prohibitively expensive. Programs such as food mail that provide access to more nutritious foods are easily accessed by people who have credit cards, but many Inuit don’t have credit cards and don’t even have bank accounts.

Delayed diagnosis of infectious cases results in prolonged exposure time for contacts. Diagnosis is delayed when regions don’t have local diagnostic capabilities and expertise.

Some remote communities lack continuity of health care providers. A successful TB program is dependent on a relationship of trust between the residents in the community and their health care providers. This requires continuity of staff and health care workers who are experienced and trained in early detection of tuberculosis.

Social colonization is the primary root cause of TB among aboriginal populations. Issues related to the social determinants of health, which include crowded and inadequate housing, poor nutritional status, and lack of continuity of health care providers, are the root causes of continued high rates amongst Inuit. TB rates in Europe began to fall even before the introduction of the first medications, with improvements to standards of living. By addressing issues such as poverty, housing, and access to health care and nutritious food, we can expect the same to happen here.”

Who’s Who

Randell, Elaine. 2010-04-20. “Social Colonization.” Evidence. Standing Committee on Health. 40th Parliament, Government of Canada. 3rd Session. Paragraph 1903660.