Table of Contents Author Guidelines Submit a Manuscript
Veterinary Medicine International
Volume 2012, Article ID 145318, 6 pages
Research Article

Detection of Bovine IgG Isotypes in a PPA-ELISA for Johne's Disease Diagnosis in Infected Herds

1Cátedra de Inmunología, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires (UBA), Chorroarín 280, Ciudad Autónoma de Buenos Aires C1427CWO, Argentina
2Laboratorio de Bacteriología, Estación Experimental Agropecuaria Balcarce, Instituto Nacional de Tecnología Agropecuaria (INTA), Ruta 226, Km 73.5, Provincia de Buenos Aires, Balcarce B7620BEN, Argentina
3Departamento de Producción Animal, Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata (UNMdP), Ruta 226, Km 73.5, Provincia de Buenos Aires, Balcarce B7620BEN, Argentina

Received 6 February 2012; Accepted 6 May 2012

Academic Editor: Michael D. Welsh

Copyright © 2012 Bárbara Fernández et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Johne's Disease or Paratuberculosis is a chronic granulomatous enteritis disease affecting ruminants. Detection of subclinically infected animals is difficult, hampering the control of this disease. The aim of this work was to evaluate the performance of detection of IgG isotypes in a PPA-ELISA to improve the recognition of cattle naturally infected with Map in different stages. A total of 108 animals from Tuberculosis-free herds were grouped as follows: exposed ( ), subclinically infected ( ), clinically infected ( ), and healthy controls ( ). Receiver-operating characteristic (ROC) curves of isotypes/PPA-ELISAs were constructed and areas under the curves were compared to evaluate the performance of each test. Our study demonstrated that the conventional PPA-ELISA (detecting IgG) is the best to identify clinically infected animals with high sensitivity (92.9%) and specificity (100%). Meanwhile, IgG2/PPA-ELISA improved the number of subclinically infected cattle detected as compared with conventional IgG/PPA-ELISA (53.8 versus 23.1%). In addition, it had the maximum sensitivity (65.0%, taking into account all Map-infected cattle). In conclusion, the combination of IgG and IgG2/PPA-ELISAs may improve the identification of Map-infected cattle in different stages of disease. The usefulness of IgG2 detection in serological tests for Johne's Disease diagnosis should be further evaluated.