Western blot analysis to identify antigenic proteins in B. mandrillaris extracts. Blots were probed with various positive sera (S-rabbit [hyperimmune rabbit serum], S-1 [patient serum], S-2 [patient serum], S-3 [patient serum], S-4 [patient serum], and S-5 [patient serum]) and negative sera (S-BD-1 [blood donor serum], S-BD-2 [blood donor serum]). Isolates used were as follows: B.m-1 (human isolate CDC:V451), B.m-3 (horse isolate CDC:V433), B.m-6 (gibbon isolate CDC:V565), and B.m-8 (human isolate CDC:V194). M, molecular mass marker.