Central nervous system involvement in rickettsial diseases

The Rickettsia are obligate intracellular parasites that are usually spread to humans by insects and typically produce vasculitides. The prototypic ri ckettsial disorder in the United States is Rocky Mountain spotted fever (RM SF). The differential diagnosis of RMSF and related disorders includes othe r conditions that produce vasculitis, most importantly meningococcemia. The rickettsial dis orders are usually treated effectively with tetracycline d erivatives.