Occurrence of false-positive results in three paratuberculosis - ELISAs performed in a tuberculous herd.
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.
Lilenbaum
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W
Veterinary Bacteriology Laboratory, Universidade Federal Fluminense, Niteroi, 24210-130, Brazil. mipwalt@vm.uff.br
Marassi
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CD
Varges
R
R
Medeiros
L
L
Oelemann
W M R
WM
Fonseca
L S
LS