I spent six weeks during the summer before senior year working at an archaeology field school in Alaska's squashy bush country. Taiga, or huge flat stretches of land where the permafrost level is about 6 inches below the surface, is mosquito-breeding heaven: With almost no hills to speak of, drainage is minimal, and water that doesn't make it to one of the slow-moving rivers ends up pooling in large shallow ponds on top of the frozen zone, broken up somewhat by muskeg, a squodgy mass of vegetation that has been described as feeling like wet mattresses. Mosquitos breed there in astronomical numbers, providing a bountiful food source for the local avifauna and attacking anything warmblooded without mercy.
Most of Alaska's wildlife is at least somewhat protected by thick bushy fur, so given the choice between trying to find a landing place on a bear's snout and diving for unprotected human flesh, the average Anopheles alaskabastardicus will invite three million of her fellows to join the Homo sapiens buffet. Oh, and due to circumstances beyond our control, we spent a night and most of two days without a netted outhouse. Our bare bums must've seemed like Christmas to the skeeters, and we all swiftly lost our senses of humor about bites in private places. We spent the six weeks in a permanent haze of Deep Woods Off, pure deet smeared on our clothes, and incense-like smoke from mosquito coils, which contain some sort of insect neurotoxin that probably doesn't do much good for humans. From where we sat, slapping incessantly at the bugs, going without some sort of chemical protection would've been the road to madness. Even our two vegans weren't above cheering the deaths of our hungry tormentors.
Obviously deet isn't really good for you, though it was the lesser of two evils. As we packed up, one of the other students grimaced, "I have a new baby niece to meet when we get home. Better hit the sauna for a few days first; if I touch her now, I think she'll shrivel up like plastic in the microwave." We did end up spending quality time in the McGrath firejumpers' sauna, trying to sweat out all the toxins in the haze of menthol-oiled steam (and the story about how that evening involved meeting various locals whilst mutually nekkid was funnier after the fact). Maybe it worked: Sarah's niece survived her first encounter with her aunt.
I'm still going with sunblock. Should the fates call me back to the bush in high summer, too, I'm still bringing the Off.