This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
Rocky mountain spotted fever is caused by - 
Select and explain. 
A. Rickettsia rickettsii, B. Rochalimaea quintana, C. Rickettsia tsutsugamushi, D. Coxiella burnetii
A: Rickettsia rickettsii
Answer: A: Rickettsia rickettsii 
Explanation: Ans. is 'a' i.e., Rickettsia Rickettsi DiseaseAgentInsect vectorMammalian reservoir1.Typhus group a. Epidemic typhusR. prowazekiiLouseHumans b. Murine typhus (Endemic typhus)R. typhiFleaRodents c. Scrub typhusR. tsutsugamushiMiteRodents2.Spotted fever group a. Indian tick typhusR. conoriiTickRodents, dogs b. Rocky mountain spotted feverR. rickettsiiTickRodents, dogs c. Rickettsial poxR. akariMiteMice3.Others a. Q feverC. burnetiiNilCattle, sheep, goats. b. Trench feverRocholimaca quintanaLouseHumans