PCR ASSAY DETECTS MANNHEIMIA HAEMOLYTICA IN CULTURE-NEGATIVE PNEUMONIC LUNG TISSUES OF BIGHORN SHEEP (OVIS CANADENSIS) FROM OUTBREAKS IN THE WESTERN USA, 2009–2010

Mannheimia haemolytica consistently causes severe bronchopneumonia and rapid death of bighorn sheep (Ovis canadensis) under experimental conditions. However, Bibersteinia trehalosi and Pasteurella multocida have been isolated from pneumonic bighorn lung tissues more frequently than M. haemolytica by...

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Published in:	Journal of wildlife diseases Vol. 50; no. 1; pp. 1 - 10
Main Authors:	Shanthalingam, Sudarvili, Goldy, Andrea, Bavananthasivam, Jegarubee, Subramaniam, Renuka, Batra, Sai Arun, Kugadas, Abirami, Raghavan, Bindu, Dassanayake, Rohana P., Jennings-Gaines, Jessica E., Killion, Halcyon J., Edwards, William H., Ramsey, Jennifer M., Anderson, Neil J., Wolff, Peregrine L., Mansfield, Kristin, Bruning, Darren, Srikumaran, Subramaniam
Format:	Journal Article
Language:	English
Published:	Business Office, 810 East 10th St., Lawrence, Kansas 66044-8897, USA Wildife Disease Association 01-01-2014
Subjects:	Animals BACTERIOLOGY AND MYCOLOGY Bibersteinia trehalosi Bighorn sheep culture die-off Disease Outbreaks - veterinary leukotoxin Mannheimia haemolytica Mannheimia haemolytica - isolation & purification Pasteurella multocida Pasteurellosis, Pneumonic - diagnosis Pasteurellosis, Pneumonic - epidemiology PCR Polymerase Chain Reaction - methods Polymerase Chain Reaction - standards Polymerase Chain Reaction - veterinary Sheep Sheep Diseases - diagnosis Sheep Diseases - epidemiology Sheep, Bighorn - microbiology Species Specificity United States - epidemiology United States
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Summary:	Mannheimia haemolytica consistently causes severe bronchopneumonia and rapid death of bighorn sheep (Ovis canadensis) under experimental conditions. However, Bibersteinia trehalosi and Pasteurella multocida have been isolated from pneumonic bighorn lung tissues more frequently than M. haemolytica by culture-based methods. We hypothesized that assays more sensitive than culture would detect M. haemolytica in pneumonic lung tissues more accurately. Therefore, our first objective was to develop a PCR assay specific for M. haemolytica and use it to determine if this organism was present in the pneumonic lungs of bighorns during the 2009–2010 outbreaks in Montana, Nevada, and Washington, USA. Mannheimia haemolytica was detected by the species-specific PCR assay in 77% of archived pneumonic lung tissues that were negative by culture. Leukotoxin-negative M. haemolytica does not cause fatal pneumonia in bighorns. Therefore, our second objective was to determine if the leukotoxin gene was also present in the lung tissues as a means of determining the leukotoxicity of M. haemolytica that were present in the lungs. The leukotoxin-specific PCR assay detected leukotoxin gene in 91% of lung tissues that were negative for M. haemolytica by culture. Mycoplasma ovipneumoniae, an organism associated with bighorn pneumonia, was detected in 65% of pneumonic bighorn lung tissues by PCR or culture. A PCR assessment of distribution of these pathogens in the nasopharynx of healthy bighorns from populations that did not experience an all-age die-off in the past 20 yr revealed that M. ovipneumoniae was present in 31% of the animals whereas leukotoxin-positive M. haemolytica was present in only 4%. Taken together, these results indicate that culture-based methods are not reliable for detection of M. haemolytica and that leukotoxin-positive M. haemolytica was a predominant etiologic agent of the pneumonia outbreaks of 2009–2010.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0090-3558 1943-3700
DOI:	10.7589/2012-09-225