As someone who has stood in all manner of mosquito infested wetlands for decades, I long ago found that natural products work—just not well or for very long. Also…be very careful when choosing natural alternatives, “oil of lemon eucalyptus” that has been tested as effective is a synthetic product…it is not at all the same as the essential oil from your local store. Just cause it smells better does not make is any better or safer. Most natural products are less repellents and more scent maskers. They usually start to fail as soon as you sweat. Some use oil as a carrier (Avon Skin so Soft classic) and they are pretty good at drowning sand fleas!
These days, it is pretty easy to find clothing impregnated with Permethrin — although it usually is only good for about 30 washes. There are also after-market treatment you can use –usually only good for 6 or so washes. However, these are really only safe for fabrics you can wash. Be very very careful about apply mosquito repellents to technical fabrics as they are severely damaged by the chemicals used to carry the repellents. Sawyer has recently made a spray that can be applied to objects (tents, chairs, and other non-washables), but still not technical fabrics.
Here some additional mosquito info:
1) Mosquitoes likely ‘see’ a target by its heat and then seek areas of the target that are hottest (meaning blood close to the skin surface). They also track carbon dioxide release.
2) Naturally released chemical like estrogen and lactic acid are attractive to them. So, women and people exercising get bitten more. A small study found pregnant women were bitten statistically more than not pregnant.
3) If you dress in dark colors, mosquito discern more of a contrast against the sky than if you wear light colors. They don’t “see” as mammals do, but that contrast is helpful for daytime hunter to focus on you.
4) If you drink beer, they will like you more. The study of a group of 13 volunteer offered no reason for why, but found vodka failed to elicit the same attraction of mosquitoes. Just beer. Likely due to some metabolite you breath out.
5) Zika carrying mosquito peak activity during daylight hours. Malaria carrying mosquitoes are at peak activity at night.
6) Often, you won’t feel the bit until it is too late (although some species hurt like hell!).
7) When looking at infection data, subtract out local peoples. Just look for data on foreign travellers. Like many diseases, most local populations have a greater level of resistence than foreign.