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: Medicine
Chikungunya is caused by ? 
Select and explain. 
A. Mosquito-borne Alphavirus, B. Mosquito-borne Beta virus, C. Mosquito-borne Gamma virus, D. Mosquito-borne Deltavirus
A: Mosquito-borne Alphavirus
Answer: A: Mosquito-borne Alphavirus 
Explanation: Chikungunya caused by a mosquito-borne alphavirus.Previous outbreaks had been confined to the tropics, and some have attributed this expansion to global warming. Ref: Harrison's Principles of Internal Medicine, 18e, Chapter 119.Introduction to Infectious Diseases.