Apart from malaria, mosquitoes in Peru also transmit yellow fever and dengue, a flu-like disease that is usually not life-threatening. Ticks and smaller insects can also transmit Chagas’ disease. With a few simple precautions against insects, Amazon visitors greatly reduce their risk of exposure to these diseases.

Begin by wearing long pants, long-sleeved shirts, good shoes, and a hat with a bandanna covering the neck. Clothes should preferably be thick enough to prevent mosquitoes from biting through, but that is hard to do in the jungle. Lighter colors, especially white, for some reason, seem to keep mosquitoes away.

Spray your clothes with a permethrin-based spray, especially cuffs and sleeves. When arriving at the lodge, spray the mosquito net over your bed with the spray as well and let it dry before sleeping. Studies show that permethrin lasts up to several weeks on clothes, even after having been washed five or six times.

Apply a DEET-based solution when mosquitoes are present. Studies have shown that 20–33 percent DEET lasts for 6–12 hours (less if you are perspiring) and that anything over that strength produces only marginal improvements in protection. DEET is a highly toxic substance, so wash it off the skin as soon as possible. Use only 10 percent DEET on kids and none at all on infants. DEET will melt any plastic bag you store it in and will also ruin jewelry.

Many lodges provide a coil that can be lit and then smokes throughout the night, releasing a mild insecticide. These seem to work quite well. Make sure your mosquito bed net is wide enough so that you don’t lie against it as you sleep—otherwise the mosquitoes will bite you right through it.

Peruvian mosquitoes, unfortunately, seem to pay no attention to natural repellents such as citronella or oils made from soybean and eucalyptus. Bring DEET-based lotion at least as a backup.