Insect Borne Diseases—How to Protect Yourself

by Fran Lessons: RN, RSN, MS

The best two behaviors for avoiding illness in tropical and developing countries are to protect yourself against insects and take food and beverage precautions. Although these two precautions seem simple, in reality many travelers succumb to diseases transmitted through insects and/or food and water.

Since we have vaccines and prophylactic medications available for some insect borne diseases, travelers often give the insect issue less attention than they should. We still do not have vaccines or medications available to treat many insect borne diseases like Dengue Fever, Lyme Disease, West Nile Virus, African Sleeping Sickness, Plague, Sand Fly Fever, Rift Valley Fever, Scrub Typhus, Leishmaniasis and Loiasis to mention just a few.

Fortunately many of the above mentioned diseases are rare for tourists but often their rareness makes them hard to recognize and treat. Therefore, the best treatment is prevention and the best prevention is a repellent with 20-30% DEET for exposed skin and Permethrin on clothing, netting, bedding and travel gear. Using the combination of DEET and Permethrin is an essential step in preventing insect bites. Used in conjunction and appropriately, you can expect 99% protection. These products are effective and necessary to safeguard your health. We do not recommend citronella, oil or plant based repellents because of their relatively poor efficacy.

Long before the advent of synthetic chemicals, people used plant-derived substances to repel mosquitoes. Plants whose essential oils are reported to have repellent activity include citronella, camphor, clove, geranium, soybean, eucalyptus, peppermint, and others. Citronella is the most common botanical oil found in natural repellents. However, when compared to DEET they only lasted from minutes to under 2 hours. Oil applied to the skin will retard mosquitoes as long as the oil sits on the skin. As soon as the oil is absorbed, the mosquitoes and other flying insects will bite.

Skin-so-soft, an oil-based skin softener received quite a bit of attention as a repellent because people noticed that they were not bitten after application. This phenomenon sparked a whole new advertising campaign for the distributor and to this day, people still believe the product has good repellent capabilities. Americans tend to stay outside for shorter periods and therefore the product may protect for a few hours if it is applied thickly. Travelers are usually outdoors for longer periods of time and if bitten, may cause a disease that is not present in the United States.

Clothing provides a physical barrier to biting insects, provided it is sufficiently thick or tightly woven. For increased protection, especially when there is more intense mosquito activity you should wear long sleeved shirts and slacks. Tucking your pant leg into your socks or boots can prevent both mosquito bites and tick attachment. In hot, humid climates, long sleeved shirts of thickly woven fabric may be uncomfortable. Clothing protection is dramatically increased when the fabric is sprayed or impregnated with Permethrin. If traveling in a group, Permethrin used by all members of the group will enhance protection for everyone in the group as a barrier ring is formed.

It also pays to give careful attention to eating and sleeping accommodations. Patronize facilities that appear clean and insect free and are either well screened or air-conditioned so that the windows can be kept tightly closed, especially during mosquito peak feeding times (dusk to dawn and on overcast or cloudy days).

Avoid open-air restaurants and outdoor buffets where food and beverages may be exposed to flying insects. Avoid wearing colognes and perfumed products wherever insects are likely to bite. Use only unscented hygiene products, such as hair sprays, deodorants and soaps. Also, avoid wearing jewelry and highly colored clothing. Dress in pale colors like light green, tan and khaki and cover up as much as possible.

Do not walk with bare feet, since many biting insects crawl on the ground or fly within several inches of it. At the beach or pool, lie on a lawn chair or at a minimum, on a blanket or long beach towel. Do not lay your clothes directly on the ground since perspiration or other scents on them may attract insects. Instead, put your clothes on a lawn chair or blanket and always inspect under collars and cuffs and shake them vigorously before putting them back on.

Avoid swimming in small ponds and lagoons. Non-moving bodies of fresh water are the favorite breeding grounds of mosquitoes. Similar cautions apply when hiking. Avoid areas near stagnant pools and marshes. And after long hikes, take a shower and check your body for embedded insects.

Now that you have taken all the necessary precautions, you must know how to select the best repellent for optimal protection, as not all repellents are equal. Although there are repellents with 20% to 30% DEET they may be made using an alcohol, oil or water base and this means that the product is absorbed or evaporates too quickly to provide long term protection. The new Passport Health Controlled Release formula uses a patented Sub Micron Encapsulation process by which the DEET is captured inside a Mircala protein. Each microscopic particle of protein contains chambers, which hold DEET. Over a period of up to 24 hours your skin slowly dissolves the protein particles. As the particles are dissolved, DEET is released from the chambers for evaporation and the dissolved proteins nourish your skin. At any point in time you may simply wash the remaining formula off your skin with soap and water.

The American Academy of Pediatrics recommends use of repellents with lower concentrations of DEET for children. Reducing unnecessary skin exposure of DEET is good for adults too. Because of the way Sub Micron Encapsulation system works, the Passport Health Controlled Release formula actually exposes the children’s skin to less DEET than traditional low DEET formulas, while increasing the level of protection.

Remember, the best way to avoid insect bites—and the diseases that insects transmit—is to apply a DEET repellent to your exposed skin and treat your clothing with Permethrin. The effectiveness of this combination is confirmed by many studies. In one such study conducted in Alaska, the use of clothing and a 30% DEET product afforded 99.9% protection. In comparison, untreated control subjects sustained over 1000 bites per hour!

Reprinted with permission from Passport Health