Johne's disease was first diagnosed in an endangered Florida Key deer (Odocoileus virginianus clavium) in 1996 and six additional Key deer deaths were documented from 1998 to 2004. We investigated the geographic distribution of Mycobacterium avium subsp. paratuberculosis in the Lower Florida Keys from February 2005 through May 2006 via collection of blood and fecal pellets from 51 live-captured deer, collection of 550 fecal samples from the ground, and by necropsies of 90 carcasses. Tissue and fecal samples also were submitted from 30 raccoons (Procyon lotor), 3 feral cats (Felis catus), an opossum (Didelphis virginiana), and a Lower Keys marsh rabbit (Sylvilagus palustris hefneri). Mycobacterium avium subsp. paratuberculosis was identified in 23 Key deer fecal samples collected from the ground, tissue samples from two clinically ill Key deer, and from the mesenteric lymph node of a raccoon. Recovery of Map from multiple samples confirms the presence and persistence of the micro-organism on Big Pine Key, Munson and Little Palm Islands. Supplemental feeding of the key deer occurs on these islands; all previous cases of Johne's disease reported since 1996 have occurred in these locations. The organism appears to be limited to this relatively small geographic area within the range of Key deer and evidence of the infection in non-ruminant animals is scant.

Key words: Florida Keys, Johne's disease, Key deer, Mycobacterium avium subsp. paratuberculosis, Odocoileus virginianus clavium, paratuberculosis, raccoon