Chikungunya alledgedly doesn't kill, although one particular area is reporting 5 deaths a day.
Yellow Fever, Dengue & Chikungunya are carried by the Aedes mosquito - black & white stripes, malaria by the Anopheles in case you wondered, and I think they are a reddy colour.
Aedes bite during the day, Anopheles during twilight & hours of dark.
I have very rarely had problems with mosquitos during the day in Goa, it's a twilight thing BUT I have splatted plenty of black & white striped mosquitos - read into that what you will .
I think Karnataka has the biggest local incidence of Chikengunya but it's like 20,000 cases per annum out of a population of 44 million, less than half a percent.
Kerala is or was on the verge of a Dengue epidemic but all that means is that significantly more cases than usual have been reported.
Only females bite! Now why doesn't that surprise me?
Both home in on body heat and CO2 so stay cool and try not to breathe out.
Either light or dark clothes also attract them, can't remember which so that's probably not much help.
Just follow the advice re mosquitos generally and keep your fingers crossed. You would be incredibly unlucky to catch either Dengue or Malaria for that matter in Goa but it is a risk. I would think you are far, far more likely to get hurt in a road accident, stung by a jelly fish, or run over by some lunatic on a jet ski than bitten by a moody Mossi in Goa.