Up until I was 50, I had never been bitten or bothered by mosquitoes then on a visit to Saklikent, I was bitten on the ankle. The following year I went to Corfu to work and I was savaged by mosquitoes. I believe that the bite I received in Saklikent, acted as a trigger. Anyway the doctor in Arillas in Corfu, applied iodine to both my legs and bandaged them (a source of great hilarity). He also gave me an injection and told me not to worry because after 3 months I would become 'Greek' and wouldn't be bothered. As it turned out, I was there initially for 8 months and as the doc said, I was never bothered. I occasionally get a bite but I do not have any itching or other side effects. I would believe that people living abroad will develop some immunity.