Try taking a multi B tablet twice a day for two weeks before you go, works a treat. I used to get smashed real bad by the little shits, but now they hardly touch me. If I do get a bite they don't bit for long and the bite mark goes down within half an hour with no itching. Or you can now buy a product from the chemist that is a combo of B and a chemical, I have heard this works really well.
Cheers. Mick.