This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Organism that does NOT need vector for transmission: 
Select and explain. 
A. Rickettsia prowazekii, B. Rickettsia rickettsii, C. Coxiella burnetii, D. Borrelia recurrentis
C: Coxiella burnetii
Answer: C: Coxiella burnetii 
Explanation: Coxiella burnetii causes Q fever. Q fever transmission differs from other rickettsial infection in that there is no ahropod involved in its transmission to man. Transmission results from inhalation, ingestion, abrasion or directly in conjunctiva. Ref: Park 21st edition, page 276.