title: Occurrence of false-positive results in three paratuberculosis - ELISAs performed in a tuberculous herd.
abstract: The interference of bovine tuberculosis (TB) on the efficacy of paratuberculosis (PTB) diagnostic tests has been evaluated. A group of 32 tuberculous cows identified by both intradermal tests and gamma-interferon assay, 16 of them confirmed by the recovery of M.bovis from tissues, was tested by three different PTB- ELISAs, being two commercials and one in-house. The rest of the adult animals of the herds, totalizing 216 TB-negative animals, were also tested as a control group. Fecal culture for PTB was negative in all animals, but seven (21.8%) tuberculous cows produced false-positive reactions when tested by various PTB-ELISAs, leading to a misdiagnosis. Tuberculosis impairs the specificity of serological tests for paratuberculosis diagnosis and should be considered for the reliability of PTB control programs.
authors.affiliation: Veterinary Bacteriology Laboratory, Universidade Federal Fluminense, Niteroi, 24210-130, Brazil. mipwalt@vm.uff.br
authors.forename: W
authors.initials: W
authors.lastname: Lilenbaum
authors.forename: C D
authors.initials: CD
authors.lastname: Marassi
authors.forename: R
authors.initials: R
authors.lastname: Varges
authors.forename: L
authors.initials: L
authors.lastname: Medeiros
authors.forename: W M R
authors.initials: WM
authors.lastname: Oelemann
authors.forename: L S
authors.initials: LS
authors.lastname: Fonseca