Figure 1. Western blot reactivity of convalescent-phase serum from a patient with spotted fever rickettsiosis with high standing titers. Antigens from the rickettsial isolates were solubilized at room termperature or boilded for 5 minutes before electrophoresis. The darkest large bands indicate R. africae, R. conorii, and Israeli tick typhus rickettsiae [ISTT] (no specificity detected). R. typhi is a member of the typhus group of rickettsiae, whereas all other isolates are members of the spotted fever group.