Evaluation of ELISA in raw milk for detection of antibodies to Mycobacterium avium subsp. paratuberculosis in dairy herd

TIERI, S; CIRONE, K; MORSELLA, C; MÉNDEZ, L; MUNDO, S; FERNÁNDEZ, B; PAOLICCHI, F

VETERINARIA ITALIANA

IST ZOOPROFILATTICO SPERIMENTALE ABRUZZO & MOLISE G CAPORALE-IZS A&M

Año: 2023

0505-401X

Paratuberculosis(PTBC) is a chronic intestinal disease of animals caused by Mycobacterium avium paratuberculosis (MAP). MAP infection is diagnosed through indirecttests based on the immune response. The aims of this study were to compare the performanceof two milk ELISA for the diagnosis of PTBC and to assess the bulk tank milk (BTM)MAP exposure in dairy cattle in Argentina. A total of 357 fecal, serum and milksamples were collected. The fecal samples were processed by culture for MAPisolation, while both, serum and milk samples were used for the detection of antibodiesby two different ELISA tests, "inhouse" and commercial kit. MAP was isolated in 3.9% of the samples of fecal.For milk ELISA poor concordances were obtained. Optimized cut-off points werecalculated. The highest sensitivity and specificity values (64% and 80%respectively) were obtained with the combination of MAP isolation andcommercial milk ELISA. The results indicate that the combination of differenttechniques to identify of dairy cattle infected with MAP increases theefficiency of diagnosis. In addition, BTM  samples (n=98) were evaluated to determineherd status using the commercial kit during two seasons, identifying 33.3% ofpositive samples in autumn and 35.4% in spring.