This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
It is true regarding Endemic typhus that - 
Select and explain. 
A. Man is the only reservoir of infection, B. Flea is a vector of the disease, C. The rash developing into eschar is a characteristic presentation, D. Culture of the etiological agent in tissue culture is a diagnostic modality
B: Flea is a vector of the disease
Answer: B: Flea is a vector of the disease 
Explanation: Rats are the reservoirs. Rat flea is the vector. Rickettsial infection is characterised by fever , headache ,malaise, prostration,skin rash and enlargement of spleen and liver. Diagnostic procedures include isolation of rickettsiae, IFA, CFT, Weil Felix test , ELISA Reference; Park&;s Textbook of preventive and social medicine, 24th edition.Pg no. 317