The area between the Great Lakes and Lake Winnipeg, bounded on the north by the Hudson Bay lowlands, is sometimes known as the "Petit Nord." Providing a link between the cities of eastern Canada and the western interior, it was a critical communication and transportation hub for the North American fur trade for over 200 years. It also became the dispersal point for waves of devastating disease. An extensive trading network, both among Aboriginal groups and fur trade society, carved a path for the diffusion of diseases such as smallpox, influenza, and measles. Over two centuries, these diseases were responsible for a monumental loss of life and forever transformed North American Aboriginal communities." "Historical geographer Paul Hackett meticulously traces the diffusion of these diseases from Europe through central Canada to the West. Hackett's analysis of evidence in fur trade journals and oral history, combined with this study of the diffusion behaviour, yields a comprehensive picture of where, when, and how the staggering impact of these epidemics was felt.