WT mice infected via the footpad with B. melitensis, B. abortus, or B. suis develop arthritis and musculoskeletal inflammation. C57BL/6 WT mice were infected in each rear footpad with 1 × 105 CFU of Brucella spp., 1 × 104 CFU of B. melitensis 16M (A, B, F to I), or 1 × 103 CFU of B. melitensis 16M or mock infected with sterile PBS (sPBS) (C and D) and evaluated for ankle swelling over time (A and C). Mice were euthanized on day 14 postinfection, and joint and spleen bacterial loads were enumerated (B and D). (A) *, P < 0.05 compared to WT mice infected with 1 × 105 CFU of B. melitensis 16M. (C) *, P < 0.05 compared to mock-infected WT mice, and error bars depict standard errors of the mean. Representative plots of H&E-stained joint sections from mock-infected mice (E) or mice infected in the footpad with 1 × 105 CFU of B. melitensis 16M (F) 1 × 105 CFU of B. suis 1330 (G), 1 × 105 CFU of B. abortus 2308 (H), 1 × 104 CFU of B. melitensis 16M (I), or 1 × 103 CFU of B. melitensis 16M (J) are shown. Images (100×) are depicted with amplified boxed regions (400×) displayed beneath each image. Data from mice infected with 1 × 105 CFU of B. melitensis 16M is representative of 2 to 3 independent experiments, while data from other Brucella strains are representative of one experiment.