Immune Responses After Oral Inoculation of Weanling Bison or Beef Calves With a Bison or Cattle Isolate of Mycobacterium Avium Subsp. Paratuberculosis

Abstract

Paratuberculosis is endemic in domestic and wild ruminants worldwide. We designed the following study to compare host immune responses and pathologic changes in beef calves and bison calves after challenge with either a cattle or bison (Bison bison) strain of Mycobacterium avium subsp. paratuberculosis. In the first part of the study, six bison and six beef calves were orally inoculated with a cattle isolate of M. avium subsp. paratuberculosis over a 2 wk period. In the second part, an additional six bison and six beef calves were similarly inoculated with a bison strain of M. avium subsp. paratuberculosis. Throughout each of the studies, blood and fecal samples were taken monthly for a 6 mo infection period. Tissue samples were obtained at necropsy for culture and histopathologic analyses. Results from this study demonstrated that bison calves were more susceptible to tissue colonization than beef calves after challenge with the cattle isolate and, conversely, that beef calves were more susceptible to the bison strain of M. avium subsp. paratuberculosis. Although lesions were minimal they were most apparent in the jejunum and distal ileum. Interferon-gamma (IFN-␥) responses were noted in some calves by 1 mo postinoculation and were sustained longer in beef calves after challenge with the bison isolate. Antibody was not detected in either beef or bison calves during the 6 mo infection period. These results indicate that the host response to strains of M. avium subsp. paratuberculosis may differ between ruminant species.

Experimental infections in young red deer(Cervus elaphus)with a bovine and an ovine strain ofMycobacterium aviumsubspparatuberculosis

“…This appears to have been successful at reproducing infections and clinical disease in these young deer. Gwozdz et al (2000) were also able to produce clinical disease in sheep using this technique, unlike many groups who have failed to produce clinical disease in cattle (Stabel et al 2003), goats (Storset et al 2001) and sheep (Stewart et al 2004) when using similar oral doses of subcultured organisms. Begg et al (2005) hypothesised that the isolation and subculture of these organisms may select fast-growing mutants of M. ptb that are less virulent, and they used lymph node-derived organisms to produce disease in weaned lambs.…”

Evaluation of a Mycobacterium avium subsp. paratuberculosisleuDMutant as a Vaccine Candidate against Challenge in a Caprine Model

“…paratuberculosis is resilient and not readily altered to trigger disease progression. Challenge with large and repeated doses of bacteria over time, immunosuppression by corticosteroids, or depletion of CD4 T cells neither accelerated colonization nor decreased the time to clinical disease (49,(51)(52)(53). Thus, studying the long-term immune response in a natural host is required and will permit a more complete analysis of how many T cell subsets are involved in the immune response to M. avium subsp.…”

A meta-analysis of the effect of dose and age at exposure on shedding ofMycobacterium aviumsubspeciesparatuberculosis(MAP) in experimentally infected calves and cows

“…The sensitivity of culture was expected to be influenced by culture method and laboratory ; however, quantitative information on culture sensitivity by laboratory/specific method is lacking and changes in culture sensitivity were therefore not accounted for in the analysis. If animals were given two or more infectious doses of MAP in a short period of time and faecal cultures were reported in months postexposure, we assumed that values of time since infection were reported as time since first dose [4,5,[26][27][28][29][30].…”