Tissue predilection sites and effect of dose on Mycobacterium avium subs. paratuberculosis organism recovery in a short-term bovine experimental oral infection model

• Published in: Research in veterinary science Vol. 80; no. 3; pp. 253 - 259
• Main Authors: Sweeney, R.W., Uzonna, J., Whitlock, R.H., Habecker, P.L., Chilton, P., Scott, P.
• Format: Journal Article
• Language: English
• Published: England Elsevier India Pvt Ltd 01-06-2006; Elsevier Limited
• Subjects: animal models; Animals; Animals, Newborn; calves; Cattle; cattle diseases; Cattle Diseases - microbiology; Colony Count, Microbial - veterinary; disease course; disease detection; Disease Models, Animal; dose response; experimental design; Experiments; Feces - microbiology; Histopathology; Immunization; infection; Infections; inoculum; Intestinal Diseases - microbiology; Intestinal Diseases - veterinary; intestinal mucosa; Johne’s disease; Lymph Nodes - microbiology; Microbiology; Mycobacterium avium; Mycobacterium avium subsp. paratuberculosis; Mycobacterium avium subsp. paratuberculosis - growth & development; Mycobacterium avium subsp. paratuberculosis - pathogenicity; Mycobacterium avium subsp. Paratuberculosis, culture; neonates; oral administration; Organisms; Paratuberculosis; Paratuberculosis - microbiology; pathogenesis; sampling; Statistics, Nonparametric; Studies; tissue analysis; tissue culture; Veterinary medicine; Mycobacterium avium subsp. Paratuberculosis, culture; Histopathology; Johne’s disease; Paratuberculosis; Cattle
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/j.rvsc.2005.07.007

The objective of this study was to develop a short-term experimental infection model for
Mycobacterium avium subsp.
paratuberculosis (MAP) in cattle, using small oral doses of organisms. Specifically, the effect of dose size was evaluated, as well as specific tissue predilection sites for recovery of MAP. Oral doses as low as 1.5
×
10
6
CFU reliably produced infection that could be detected 3 weeks following infection. Detection of infection required culture of multiple intestinal samples (jejunum and ileum) for MAP. Histological examination did not permit detection at this early stage. Results from this study suggest intestinal mucosa, rather than tonsil, as the primary portal of entry for MAP. The experimental infection model described here is useful for studying the early effects of preventive and therapeutic interventions for paratuberculosis in cattle.