<prompt> Chikungunya is caused by ?Mosquito-borne AlphavirusMosquito-borne Beta virusMosquito-borne Gamma virusMosquito-borne Deltavirus  <response>: 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: Harrisons Principles of Internal Medicine, 18e, Chapter 119.Introduction to Infectious Diseases. 