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Title: Pasteurellosis Transmission Risks between Domestic and Wild Sheep

item Knowles Jr, Donald

Submitted to: Council for Agricultural Science and Technology Issue Paper
Publication Type: Review Article
Publication Acceptance Date: 8/1/2008
Publication Date: 8/12/2008
Citation: Miller, M.W., Knowles Jr, D.P., Bulgin, M. 2008. Pasteurellosis Transmission Risks between Domestic and Wild Sheep. Council for Agricultural Science and Technology Issue Paper. QTA2008-1.

Interpretive Summary: Pneumonia has been documented as one of the major contributors to bighorn sheep population decline. A number of infectious agents have been associated with bighorn pneumonia. This Council for Agricultural Science and Technology (CAST) report summarizes the current state of knowledge concerning bighorn sheep pneumonia including discussion of risks presented by domestic and bighorn sheep contact.

Technical Abstract: Disease has contributed significantly to the decline of bighorn sheep (Ovis canadensis) populations throughout much of western North America, decreasing their abundance and imperiling some native populations and subspecies. According to historical accounts (e.g., Grinnell 1928; Honess and Frost 1942; Shillinger 1937; Warren 1910), epidemics in some locations coincided with the advent of domestic livestock grazing in bighorn ranges, suggesting that novel pathogens may have been introduced into some bighorn populations beginning in the 1800s. Native North American wild sheep species ' bighorn sheep and thinhorn (Dall’s and Stone's) sheep (O. dalli) ' are very susceptible to pneumonia and particularly to pasteurellosis, the generic term used here for disease (often respiratory) caused by bacteria in the family Pasteurellaceae but now classified in the genera Pasteurella, Mannheimia, or Bibersteinia (reviewed by Miller 2001). In some recent pneumonia epidemics in bighorns the cause has been attributed to endemic respiratory pathogens or strains of Pasteurellaceae (Rudolph et al. 2007) and in others the cause has been attributed to Pasteurellaceae strains or other pathogens introduced via interactions with domestic sheep (O. aires; George et al. 2008). This Commentary reviews current knowledge on pneumonic pasteurellosis in domestic and wild sheep, the risks of transmission between these species, and approaches for lowering the overall risk of epidemics in wild sheep.