title: The histopathologic diagnosis of subclinical Johne's disease in North American bison (Bison bison).
abstract: The morphologic changes of subclinical Johne's disease in North American Bison (Bison bison) are characterized by microgranulomas composed of epithelioid macrophages and individual multinucleate giant cells of Langhans'-type occasionally containing individual cytoplasmic acid-fast bacilli compatible with Mycobacterium avium paratuberculosis. The microgranulomas are best visualized in the mesenteric lymph nodes of infected subclinical animals. Macrophages that can be confused with infection-associated epithelioid macrophages in the mesenteric lymph nodes are pigment-carrying cells from the intestinal tract. Mesenteric lymph node biopsy may be a useful diagnostic tool for detection of mild subclinical infection in individual ruminants from herds of unknown infection status. The biopsy may also be useful for Johne's disease surveillance during test-and-cull programs.
authors: Department of Pathobiology, College of Veterinary Medicine, University of Florida, Box 110880, Gainesville, FL 32611, USA. buergeltc@mail.vetmed.ufl.edu
authors: C D
authors: CD
authors: Buergelt
authors: P E
authors: PE
authors: Ginn
mesh_terms: D000818:Animals; D001706:Biopsy / Q000662:veterinary; D016164:Bison; D005260:Female; D007801:Langerhans Cells / Q000382:microbiology; D008198:Lymph Nodes / Q000382:microbiology / Q000473:pathology*; D008264:Macrophages / Q000382:microbiology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000302:isolation & purification; D010283:Paratuberculosis / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology*