Evaluation of the single cervical skin test and interferon gamma responses to detect Mycobacterium bovis infected cattle in a herd co-infected with Mycobacterium avium subsp. paratuberculosis

Juan Seva*, Jose M. Sanes, Guillermo Ramis, Alberto Mas, Juan J. Quereda, Bernardo Villarreal-Ramos, David Villar, Francisco J. Pallares

*Awdur cyfatebol y gwaith hwn

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

22 Dyfyniadau(SciVal)

Crynodeb

This study reports the performance of the single intradermal tuberculin (SIT) test and the interferon-gamma (IFN-γ) assay for Mycobacterium bovis in a cattle herd with high prevalence of paratuberculosis (PTB). A total of 58/350 animals were selected for necropsy based on one or more of the following criteria: positive to SIT, IFN-γ, a breeding cow that seroconverted to PTB and showed signs compatible with a wasting disease. Infection status was determined by post mortem diagnostic tests that included histopathology examination, mycobacterial cultures and PCR identification for M. bovis and Mycobacterium avium subsp. paratuberculosis (MAP). In 7/58 animals primary tuberculosis (TB) lesions, affecting only the retropharyngeal and/or mediastinal lymph nodes, were found; 3/7 animals were found SIT positive. PTB was confirmed in 35/58 animals, of which 30 had seroconverted and 14 had typical clinical signs. 45/58 animals were IFN-γ+ using the most stringent criterion (cut-off point≥0.05); however, IFN-γ test was only positive in 33 animals when using a higher threshold (cut-off point≥0.1). Three animals co-infected also showed extensive TB and diffuse PTB lesions. These results show that the combined use of SIT and IFN-γ, as interpreted using official guidelines, detected all confirmed cases of TB. Individually, the sensitivity of the SIT was inadequate to diagnose TB-positive animals with an advanced stage of PTB. The large number of IFN-γ+ animals with no visible TB lesion could be due, in part, to some protection conferred by prior infection with MAP.

Iaith wreiddiolSaesneg
Tudalennau (o-i)139-146
Nifer y tudalennau8
CyfnodolynVeterinary Microbiology
Cyfrol171
Rhif cyhoeddi1-2
Dyddiad ar-lein cynnar03 Ebr 2014
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 01 Meh 2014

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