title: Evaluation of diagnostic assays for the serological detection of Actinobacillus pleuropneumoniae on samples of known or unknown exposure.
abstract: Accurate diagnosis of exposure to Actinobacillus pleuropneumoniae is important for maintaining negative farms. In the present study, the ability of a dual-plate complement fixation (CF) assay and 3 commercially available enzyme-linked immunosorbent assays (ELISAs; quad-plate ELISA-1, single-plate ELISA-2, and single-plate ELISA-3) in detecting serological evidence of A. pleuropneumoniae exposure was compared using serum samples of experimentally infected or vaccinated pigs, or field samples from the United States. Forty-two pigs were divided into groups of 2 pigs and were inoculated with 1 of 15 A. pleuropneumoniae strains representing all known serovars of A. pleuropneumoniae, or with Actinobacillus suis, or were vaccinated with a bacterin containing A. pleuropneumoniae serovar 1, 3, 5, or 7. Serum samples collected at the day of inoculation or vaccination and 7, 14, 21, and 28 days later were used to compare the assays. On samples from experimentally infected pigs, the dual-plate CF assay, quad-plate ELISA-1, single-plate ELISA-2, and single-plate ELISA-3 had sensitivities of 0.46, 0.74, 0.13, and 0.13 and specificities of 0.90, 1.0, 1.0, and 1.0, respectively. Vaccinated pigs were identified only by the dual-plate CF assay and the quad-plate ELISA-1. In addition, 90 serum samples with unknown A. pleuropneumoniae exposure collected under field conditions were tested with all assays. The agreement of the 4 assays on field samples was slight to fair. While several assays are available for demonstration of A. pleuropneumoniae exposure, differences in assay targets complicate test choices. Decisions on which assay or combination of assays to use depend on the specific reasons for running the assays.
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA. tanjaopr@iastate.edu
authors.forename: Tanja
authors.initials: T
authors.lastname: Opriessnig
authors.forename: Michelle
authors.initials: M
authors.lastname: Hemann
authors.forename: John K
authors.initials: JK
authors.lastname: Johnson
authors.forename: Sheila
authors.initials: S
authors.lastname: Heinen
authors.forename: Luis G
authors.initials: LG
authors.lastname: Giménez-Lirola
authors.forename: Kevin C
authors.initials: KC
authors.lastname: O'Neill
authors.forename: Hai
authors.initials: H
authors.lastname: Hoang
authors.forename: Kyoung-Jin
authors.initials: KJ
authors.lastname: Yoon
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gottschalk
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Halbur
mesh_terms: D000189:Actinobacillus Infections / Q000097:blood / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000302:isolation & purification*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D003168:Complement Fixation Tests / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D011897:Random Allocation; D012680:Sensitivity and Specificity; D013552:Swine; D013553:Swine Diseases / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology*
chemical_list: D000907:Antibodies, Bacterial