title: Comparison of Buffered, Acidified Plate Antigen to Standard Serologic Tests for the Detection of Serum Antibodies to Brucella abortus in Elk (Cervus canadensis).
abstract: Brucellosis (caused by the bacterium Brucella abortus) is a zoonotic disease endemic in wild elk (Cervus canadensis) of the Greater Yellowstone Ecosystem, US. Because livestock and humans working with elk or livestock are at risk, validated tests to detect the B. abortus antibody in elk are needed. Using the κ-statistic, we evaluated the buffered, acidified plate antigen (BAPA) assay for agreement with the results of the four serologic tests (card test [card], complement fixation test [CF], rivanol precipitation plate agglutination test [RIV], standard plate agglutination test [SPT]) that are approved by the US Department of Agriculture for the detection of the B. abortus antibody in elk. From 2006 to 2010, serum samples collected from elk within B. abortus-endemic areas (n = 604) and nonendemic areas (n = 707) and from elk culture-positive for B. abortus (n = 36) were split and blind tested by four elk serum diagnostic laboratories. κ-Values showed a high degree of agreement for the card (0.876), RIV (0.84), and CF (0.774) test pairings and moderate agreement for the SPT (0.578). Sensitivities for the BAPA, card, RIV, CF, and SPT were 0.859, 0.839, 0.899, 1.00, and 0.813, whereas specificities were 0.986, 0.993, 0.986, 0.98, and 0.968, respectively. The positive predictive values and the negative predictive values were calculated for 2.6%, 8.8%, and 16.2% prevalence levels. These findings suggest the BAPA test is a suitable screening test for the B. abortus antibodies in elk.
authors.affiliation: 1  Veterinary Services, Animal and Plant Health Inspection Service, US Department of Agriculture, 187 E Tobiano Trail, Belgrade, Montana 59714, USA.
authors.forename: P Ryan
authors.initials: PR
authors.lastname: Clarke
authors.affiliation: 2  Wildlife Disease Laboratory, Wyoming Game and Fish Department, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Edwards
authors.affiliation: 3  National Veterinary Services Laboratories, Veterinary Services, Animal and Plant Health Inspection Service, 1920 Dayton Avenue, Ames, Iowa 50010, USA.
authors.forename: Steven G
authors.initials: SG
authors.lastname: Hennager
authors.affiliation: 4  Marsh Laboratory, Montana Department of Livestock, S 19th and Lincoln St., Bozeman, Montana 59718, USA.
authors.forename: Jean F
authors.initials: JF
authors.lastname: Block
authors.affiliation: 5  Idaho State Diagnostic Laboratory, Veterinary Services, Animal and Plant Health Inspection Service, US Department of Agriculture, 2230 Old Penitentiary Road, Boise, Idaho 83712, USA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Yates
authors.affiliation: 6  Risk Assessment Division, Office of Public Health and Science, Food Safety Inspection Service, US Department of Agriculture, 2150 Centre Avenue, Building D, Fort Collins, Colorado 80526, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Ebel
authors.affiliation: 7  Marsh Laboratory, Veterinary Services, Animal and Plant Health Inspection Service, US Department of Agriculture, S 19th and Lincoln St., Bozeman, Montana 59718, USA.
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Knopp
authors.affiliation: 4  Marsh Laboratory, Montana Department of Livestock, S 19th and Lincoln St., Bozeman, Montana 59718, USA.
authors.forename: Antonio
authors.initials: A
authors.lastname: Fuentes-Sanchez
authors.affiliation: 2  Wildlife Disease Laboratory, Wyoming Game and Fish Department, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Jennings-Gaines
authors.affiliation: 8  Animal Health Laboratory, Idaho State Department of Agriculture, 2230 Old Penitentiary Road, Boise, Idaho 83712, USA.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Kientz
authors.affiliation: 8  Animal Health Laboratory, Idaho State Department of Agriculture, 2230 Old Penitentiary Road, Boise, Idaho 83712, USA.
authors.forename: Marilyn
authors.initials: M
authors.lastname: Simunich
mesh_terms: D000372:Agglutination Tests / Q000379:methods / Q000662:veterinary*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D002003:Brucella abortus / Q000276:immunology*; D002006:Brucellosis / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D003670:Deer / Q000097:blood / Q000276:immunology / Q000382:microbiology*; D012698:Serologic Tests / Q000379:methods / Q000662:veterinary*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial
keywords: Brucella abortus; buffered antigen plate agglutination (BAPA); elk; negative predictive value; positive predictive value; sensitivity; specificity; κ-statistic