CD40LG and Rickettsiosis: Among 28 febrile patients in Sri Lanka with fever persisting for more than 7 days, who responded to empirical treatment of doxycycline, 11 (39%) patients were confirmed by serology (IgM, IgG) as having spotted fever group rickettsioses and 10 (36%) as having Orientia tsutsugamushi infection [35].