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Title: Concordance in diagnostic testing for respiratory pathogens of Bighorn Sheep

Author
item WALSH, DANIEL - Us Geological Survey (USGS)
item CASSIRER, FRANCES - Idaho Department Of Fish & Game
item BONDS, MICHAEL - Us Geological Survey (USGS)
item BROWN, DANIEL - University Of Florida
item EDWARDS, WILLIAM - Wyoming Department Of Game & Fish
item WEISER, GLEN - University Of Idaho
item DREW, MARK - Idaho Department Of Fish & Game
item Briggs, Robert
item FOX, KAREN - Colorado Parks And Wildlife
item MILLER, MICHAEL - Colorado Parks And Wildlife
item SHANTHALINGAM, SUDARVILI - Washington State University
item SRIKUMARAN, SUBRAMANIAM - Washington State University
item BESSER, THOMAS - Washington State University

Submitted to: Wildlife Society Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/6/2016
Publication Date: 12/5/2016
Citation: Walsh, D.P., Cassirer, F.E., Bonds, M.D., Brown, D.R., Edwards, W.H., Weiser, G.C., Drew, M.L., Briggs, R.E., Fox, K.A., Miller, M.W., Shanthalingam, S., Srikumaran, S., Besser, T.E. 2016. Concordance in diagnostic testing for respiratory pathogens of Bighorn Sheep. Wildlife Society Bulletin. 40(4):634-642. doi: 10.1002/wsb.721.

Interpretive Summary: Reliable diagnostic tests are essential for disease investigation and management. To evaluate reliability of diagnostic testing for respiratory pathogens of bighorn sheep (Ovis canadensis), we conducted a series of ring tests across 6 laboratories routinely involved in detection of bighorn bacterial pathogens and 3 reference laboratories. Consistency of results for replicate samples within laboratories high, and consistency between laboratories was generally high. Most errors on defined status samples were false negatives, suggesting test sensitivity was a greater problem than specificity. Despite differences in testing protocols, median agreement among laboratories and correct classification of controls for most agents was =0.80, meeting or exceeding the standard required by federal proficiency testing programs. This information is valuable for interpreting test results, for laboratory quality assessments, and for advancing diagnosis of respiratory disease in wild sheep.

Technical Abstract: Reliable diagnostic tests are essential for disease investigation and management. This is particularly true for diseases of free-ranging wildlife where sampling is logistically difficult precluding retesting. Clinical assays for wildlife diseases frequently vary among laboratories because of lack of appropriate standardized commercial kits. Results of diagnostic testing may also be called into question when investigators report different etiologies for disease outbreaks, despite similar clinical and pathologic findings. To evaluate reliability of diagnostic testing for respiratory pathogens of bighorn sheep (Ovis canadensis), we conducted a series of ring tests across 6 laboratories routinely involved in detection of Mycoplasma ovipneumoniae, Pasteurellaceae, and/or lktA (the Pasteurellaceae gene encoding leukotoxin) and 3 reference laboratories. Consistency of results for replicate samples within laboratories was high (median agreement = 1.0). Agreement between laboratories was high for PCR detection of M. ovipneumoniae and culture isolation of Mannheimia spp. and Bibersteinia trehalosi (median agreement 0.89 – 0.95, Kappa 0.65 - 0.74), and lower for PCR detection of Mannheimia spp. lktA (median agreement 0.58, Kappa 0.12). Most errors on defined status samples were false negatives, suggesting test sensitivity was a greater problem than specificity. However, tests for M. haemolytica and lktA yielded some false positive results. Despite differences in testing protocols, median agreement among laboratories and correct classification of controls for most agents was =0.80, meeting or exceeding the standard required by federal proficiency testing programs. This information is valuable for interpreting test results, for laboratory quality assessments, and for advancing diagnosis of respiratory disease in wild sheep.