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Title: Causes of pneumonia epizootics among bighorn sheep, western United States, 2008-2010

item BESSER, THOMAS - Washington State University
item Highland, Margaret
item BAKER, KATHERINE - Washington State University
item CASSIRER, FRANCES - Idaho Department Of Fish & Game
item ANDERSON, NEIL - Fish Wildlife And Parks
item RAMSEY, JENNIFER - Fish Wildlife And Parks
item MANSFIELD, KRISTIN - Washington Department Of Fish & Wildlife
item BRUNING, DARREN - Animal And Plant Health Inspection Service (APHIS)
item WOLFF, PEREGRINE - Nevada Department Of Wildlife
item SMITH, JOSHUA - South Dakota State University
item JENKS, JONATHAN - South Dakota State University

Submitted to: Emerging Infectious Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2012
Publication Date: 3/16/2012
Citation: Besser, T.E., Highland, M.A., Baker, K., Cassirer, F.E., Anderson, N.J., Ramsey, J.M., Mansfield, K., Bruning, D.L., Wolff, P., Smith, J.B., Jenks, J.A. 2012. Causes of pneumonia epizootics among bighorn sheep, western United States, 2008-2010. Emerging Infectious Diseases. 18(3):406-14.

Interpretive Summary: This report strongly correlates the presence of Mycoplasma ovipneumoniae in herds of bighorn sheep experiencing population limiting pneumonia. This bacterial pathogen joins the list of organisms that have been identified in lung tissues from bighorn sheep with pneumonia.

Technical Abstract: Epizootic pneumonia of bighorn sheep is a devastating disease of uncertain etiology. To help clarify the etiology, we used culture and culture-independent methods to compare the prevalence of the bacterial respiratory pathogens Mannheimia haemolytica, Bibersteinia trehalosi, Pasteurella multocida, and Mycoplasma ovipneumoniae in lung tissue from 44 bighorn sheep from herds affected by 8 outbreaks in the western United States. M. ovipneumoniae, the only agent detected at significantly higher prevalence in animals from outbreaks (95%) than in animals from unaffected healthy populations (0%), was the most consistently detected agent and the only agent that exhibited single strain types within each outbreak. The other respiratory pathogens were frequently but inconsistently detected, as were several obligate anaerobic bacterial species, all of which might represent secondary or opportunistic infections that could contribute to disease severity. These data provide evidence that M. ovipneumoniae plays a primary role in the etiology of epizootic pneumonia of bighorn sheep.