First identification of Mycobacterium avium paratuberculosis sheep strain in Argentina

We here identified for the first time the presence of Mycobacterium avium paratuberculosis (MAP) sheep (S) strain in Argentina. IS900 polymerase chain reaction (PCR) was positive. The S strain was compared with MAP cattle (C) strains by using IS1311 PCR-restriction endonuclease analysis (PCR-REA), multiplex PCR and restriction fragment length polymorphism (RFLP) analysis.Fil: Traveria, Gabriel. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Clinica. Centro de Diagnostico E Investigaciones Veterinarias; ArgentinaFil: Zumárraga, Martín José. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Etchechoury, Ignacio. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Romano, Maria Isabel. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cataldi, Angel Adrian. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alvarado Pinedo, M. F.. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Clinica. Centro de Diagnostico E Investigaciones Veterinarias; ArgentinaFil: Pavlik, I.. Veterinary Research Institute; República ChecaFil: Pribylova, R.. Veterinary Research Institute; República ChecaFil: Romero, J. R.. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Clinica. Centro de Diagnostico E Investigaciones Veterinarias; Argentin

Development and diagnostic validation of an ELISA based on an antigenic mixture for the detection of bovine tuberculosis

Programs for the eradication of bovine tuberculosis (bTB) focus on the tuberculin skin test (TST) and slaughter of reactor cattle. However, the disease remains an animal health concern in several countries and improving the efficiency of the TST has become a critical issue. The detection of Mycobacterium bovis antibodies in serum, within weeks after the TST, may be a rapid and inexpensive way to improve bTB control. This study reports the validation of an enzyme-linked immunosorbent assay (ELISA) to detect bovine tuberculosis as an ancillary test to TST in dairy farms in Argentina. The estimated validation parameters were within the established requirements of the World Organization for Animal Health (OIE). The test demonstrated high repeatability, with coefficients of variation <25%. High test reproducibility through interlaboratory testing was also found, with an estimated Pearson coefficient of 0.9648 (95% confidence intervals 0.9315–0.9820). The ELISA detected tuberculous cattle unidentified by the TST. Of 43 animals sent to slaughterhouses that were ELISA positive 15–17 days after a negative TST, 36 were confirmed as infected with M. bovis by histopathology and IS6110 PCR. According to ROC curve analysis of results of 145 cattle from M. bovis-free herds and the 36 M. bovis-infected cattle, at a corrected optical density cut-off point of 0.3853, specificity was 95.95% and the positive predictive value at this cut-off was 83.72%. The ELISA detection test validated in this study could be readily applied in dairy farms, to complement a prior TST and improve livestock health.Instituto de BiotecnologìaFil: Griffa Natanael. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moyano, Roberto Damian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Canal, Ana María. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: Traveria, Gabriel Eduardo. Universidad de La Plata. Facultad de Ciencias Veterinarias. Centro de Diagnóstico e Investigaciones Veterinarias; ArgentinaFil: Santangelo, María De La Paz. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alonso Maria Natalia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romano, Maria Isabel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Protection efficacy of Argentinian isolates of Mycobacterium avium subsp. paratuberculosis with different genotypes and virulence in a murine model

Paratuberculosis is a chronic disease caused by Mycobacterium avium subsp. paratuberculosis (Map). The disease causes economic losses and, therefore, it is imperative to follow proper control strategies, which should include an effective vaccine. Several strategies have assessed the virulence and immune response of Map strains that could be used as a vaccine. This study evaluates the degree of virulence, immune response, and protection of Argentinian strains of Map with different genotype in a murine model. Four local isolates (Cattle type) with different genotypes (analyzed by MIRU-VNTR and SSRs) were selected and evaluated in a virulence assay in BALB/c mice. This assay allowed us to differentiate virulent and low-virulence Map strains. The less virulent strains (1543/481 and A162) failed to induce a significant production of the proinflammatory cytokine IFNg, whereas the virulent strain 6611 established infection along with a proinflammatory immune response. On the other hand, the virulent strain 1347/498 was efficient in establishing a persistent infection, but failed to promote an important Th1 response compared with 6611 at the evaluated time. We selected the low-virulence strain 1543/498 as a live vaccine and the virulent strain 6611 as a live and inactivated vaccine in a protection assay in mice. Strain 1543/481 failed to protect the animals from challenge, whereas strain 6611, in its live and inactivated form, significantly reduced the CFUs count in the infected mice, although they had different immunological response profiles. The inactivated virulent strain 6611 is a potential vaccine candidate against paratuberculosis to be tested in cattle.Instituto de BiotecnologíaFil: Colombatti Olivieri, Maria Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moyano, Roberto Damian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Traveria, Gabriel Eduardo. Universidad de La Plata. Facultad de Ciencias Veterinarias. Centro de Diagnóstico e Investigaciones Veterinarias; ArgentinaFil: Alvarado Pinedo, María Fiorella. Universidad de La Plata. Facultad de Ciencias Veterinarias. Centro de Diagnóstico e Investigaciones Veterinarias; ArgentinaFil: Mon, Maria Laura. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gravisaco, María José. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Delgado, Fernando Oscar. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; ArgentinaFil: Santangelo, María De La Paz. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romano, Maria Isabel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin