there is no rash in ehrlichiosis(caused by E. chaeffensis/E.equii) RMSF(rocky mountain spotted fever)--caused by Rickettsia rickettsiae --rash is petechial; appears on 3-6th day other Sx r the same--myalgia/ fever/ malaise ___________________ I hear and I forget. I see and I remember. I do and I understand. --Confucius