Insect Repellents, Insecticides, and Tips
Insects carry illness. Mosquitoes, tics, and other insects carry viruses, bacteria, and parasites that cause diseases such as Yellow Fever, Dengue Fever, Lyme disease, and Malaria. Malaria alone kills an estimated half a million people per year and causes illness in tens of millions (Summary Of World Malaria Report 2018, WHO).
Your risk of insect-related illness as a traveler to a destination is usually less than that of someone living there. This has to do with amount of time you spend in a particular location during a trip (days or weeks, rather than years). Yet, even with brief stays, illness certainly can occur. In one long-term observational study, it was estimated that 30,000 travelers a year come down with Malaria worldwide. (BioMed Central).
The difference between getting very sick and staying healthy while traveling often comes down to how closely you stick to insect precautions.
THERE ARE MANY THINGS YOU CAN DO TO HELP PREVENT INSECT BITES
- BE AWARE of when and where insects bite and try to adjust your activities accordingly.
Mosquitoes that can carry Zika, Dengue Fever, and Chikungunya, for example, are active during daylight hours. Mosquitoes that carry Malaria are more active dusk until dawn. Tics are generally found in wooded areas.
- WEAR APPROPRIATE CLOTHING (if the climate allows it!). Long-sleeved shirts, long pants, closed shoes and hats. Tuck your pants into your shoes.
- CHECK FOR TICS and other insects after you have been outdoors.
- BED NETS, bed nets, bed nets! If you are staying somewhere that is not adequately screened-in or air-conditioned, bed nets are essential! They are even more protective if you treat them with permethrin (protection can last for months) or are factory pre-treated (lasts even longer). Room foggers, mosquito coils, and other techniques to get rid of insects in rooms have not been well studied and can even be dangerous if not used properly, so they are generally not recommended.
- USE SKIN REPELLENTS. The CDC has identified the following active ingredients in U.S. insect repellents as providing reasonably long-lasting protection:
DEET, Picaridin, Oil of lemon eucalyptus (OLE), and IR3535.
DEET and Picardin are synthetic, while OLE and IR3535 are considered natural-occurring or synthesized from natural-occurring substances.
Higher percentages of the “active” ingredient in insect repellent affects the length of time the spray may be effective, but a higher percentage does not make a repellent MORE effective.
Other General Principles of Use of Repellents:
- All of the repellents listed above are considered safe in pregnancy if used correctly.
- Apply your sunscreen, allow it to dry for up to 20 minutes, then apply insect repellent.
- Repellents may affect the SPF of the sunscreen. Use a higher number SPF if using insect repellent.
- Avoid combination sunscreen/repellent products…you end up using too little sunscreen and too much repellent.
- If you are still getting bitten frequently using one repellent, try another!
Repellant Details and Recommended Concentrations…
– DEET: Recommended use at 30-100% concentration. Maximum of 30% in children (As per the American Academy of Pediatrics). Minimum age of use: 2 months. There is more data on effectiveness on DEET than other insect repellents. DEET should ideally be applied three times a day (perhaps twice a day for 100%, though debatable). Some people do not like DEET’s odor, it tends to be greasy, and, at higher concentrations, it can dissolve synthetic materials (excluding nylon and some of the newer synthetics).
– PICARDIN: 20%. Less than 20% is likely significantly less effective than 30% DEET. Minimum age of use: 2 months. Less odor, usually, than DEET and OK with most synthetics. Recommended application is generally three times a day.
– OLE: 30%. Not recommended under 3 years of age. Effectiveness likely shorter-duration that DEET or Picardin. Avoid the “pure” oil, since there is no data on its use as a repellent.
– IR3535: 20%. Minimum age of use: 2 months. Also considered less effective than DEET or Picardin.
- USE INSECTICIDES (and possibly repellents) on clothing and gear:
Permethrin: Clothing, hats, shoes, bed nets, jackets, and camping gear can be treated with permethrin (an anti-parasite that kills insects when they make contact with it or eat it) for significant added protection vs. untreated clothing, bed nets, etc.. The treatment will last through several washings if applied to clothing and dozens of washings if it is added to clothing or other items during manufacturing. Note: Permethrin is generally only toxic in very large quantities but, nevertheless, it is not meant for use on skin, unless you are treating diseases such as Scabies! DO NOT APPLY IT TO YOUR SKIN. Insect repellents can also be used on clothing, but need to be applied frequently, can become a mess, and DEET can harm synthetics.
PRECAUTIONS WHEN USING INSECT REPELLANTS
- Do not spray on your face. Either use a repellent cream or spray on your hands and then apply it to you face away from your eyes, nose, and mouth.
- Wash your hands after using repellent.
- Apply repellents only to exposed, uninjured skin or clothing, not under clothing.
- Wash your hands after application and wash of the rest of your skin once a day.
- Reapply after swimming or bathing.
- For children, apply to your hands and then to their skin. At our NYC Travel Clinic, we generally recommend using a cream rather than a spray for children, since even spraying it on your hands can become messy and risks you and your children inhaling the repellent.
Further general insect avoidance information, as well as information regarding individual insect-borne diseases, can be found at www.cdc.gov. With any insect repellent, chemical, or travel-heath related product you buy, always read the label very carefully for details of use and precautions. Consider contacting the manufacturer if you have any specific questions about a product.
One final note: My wife and I use DEET (30%) or Picardin (20%) on our kids and treat their outer clothing with Permethrin as needed. We both use DEET when we travel, hike, etc. (Travelers who I see in consultation often want to know what I use on my own family)
Have a great and safe trip!!