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A conceptual model of tuberculosis transmission risk in free-ranging bison herds of northern Canada

Tuberculosis transmission in free-ranging bison of northern Canada is of significant
concern to wildlife managers because of its effects on condition and mortality in bison herds and
the potential for transmission to local hunters and neighbouring cattle populations. The chronic
nature of tuberculosis combined with the gregarious behaviours of bison permit its persistence in
free-ranging herds even at low densities, which makes disease eradication difficult without
whole herd depopulation. The protection of remaining non-infected free-ranging bison
populations is thus of paramount importance to the conservation of specific disease-free wild
bison in northern Canada and to the economic stability of cattle farms. Detection of movements
and removal of dispersing animals between spatially separated free-ranging populations reduces
the potential for contact between bison populations and minimizes the probability of tuberculosis
transmission. In this thesis, a conceptual model was developed to assess the potential for
tuberculosis transmission between two infected bison herds (Nyarling River and Garden River)
in Wood Buffalo National Park and the spatially separated, Mackenzie Bison herd in the
Northwest Territories. This conceptual model identifies gaps in knowledge and highlights areas
where research is required to ensure accurate evaluation of tuberculosis transmission risk in freeranging
bison. The main finding was that the bison cohort representing the highest risk for
tuberculosis transmission between spatially separated free-ranging herds is mature males. The
propensity of mature males to make long-distance movements is also not fully understood and
research to predict these movements would make a significant contribution to risk assessment
and management planning to reduce the probability of contact between infected and non-infected
bison populations.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BRC.10170/484
Date04 April 2012
CreatorsDewar, David
ContributorsGates, C. Cormack, Boydell, Tony, Noble, Michael-Anne
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
Detected LanguageEnglish

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