Most serious form of Rickettsial disease -
Ans. is 'd' i.e.,Rocky mountain spotted fever "Among the Rickettsial diseases, Rocky mountain spotted fever is the most common and the most serious"The microbial chalonge "R rickettsii (causative agent of RMSF) is the most virulent Rickettsia" -- Clinical microbiology
Scrub typhus
Q-fever
Trench fever
Rocky mountain spotted fever