DETECTION OF BOVINE IgG ISOTYPES IN A PPA-ELISA FOR THE DIAGNOSIS OF PARATUBERCULOSIS IN INFECTED HERDS

FERNÁNDEZ, B.; GILARDONI, L.R.; JOLLY, A; COLAVECCHIA, SB.; PAOLICCHI, F.A.; MUNDO, S. L.

Buenos Aires

Jornada; II Jornadas de Jóvenes investigadores en Ciencias Veterinarias; 2012

Facultad de Ciencias. Veterinarias, UBA

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 bovines naturally infected with Map in different stages. A total of 108 bovines from Tuberculosis-free herds were grouped as: exposed (n = 30), subclinically infected (n = 26), clinically infected (n = 14), and healthy controls (n = 38). 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 bovines detected as compared with conventional IgG/PPA-ELISA (53.8 vs. 23.1 %). Besides, it had the maximum sensitivity (65.0 %, taking into account all Map-infected bovines). In conclusion, the combination of IgG and IgG2/PPA-ELISAs may improve the identification of Map-infected bovines in different stages. The usefulness of IgG2 detection in serological tests for Paratuberculosis diagnosis should be further evaluated.