title: Tissue predilection sites and effect of dose on Mycobacterium avium subs. paratuberculosis organism recovery in a short-term bovine experimental oral infection model.
abstract: 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 x 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.
authors.affiliation: Department of Clinical Studies-New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, 382 West Street Road, Kennett Square, PA 19348, USA. rsweeney@vet.upenn.edu
authors.forename: R W
authors.initials: RW
authors.lastname: Sweeney
authors.forename: J
authors.initials: J
authors.lastname: Uzonna
authors.forename: R H
authors.initials: RH
authors.lastname: Whitlock
authors.forename: P L
authors.initials: PL
authors.lastname: Habecker
authors.forename: P
authors.initials: P
authors.lastname: Chilton
authors.forename: P
authors.initials: P
authors.lastname: Scott
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D015169:Colony Count, Microbial / Q000662:veterinary; D004195:Disease Models, Animal; D005243:Feces / Q000382:microbiology; D007410:Intestinal Diseases / Q000382:microbiology / Q000662:veterinary*; D008198:Lymph Nodes / Q000382:microbiology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000254:growth & development* / Q000472:pathogenicity; D010283:Paratuberculosis / Q000382:microbiology*; D018709:Statistics, Nonparametric