Insect Precautions — Permethrin, Deet, and Picaridin
What is Permethrin?
Permethrin is a synthetic form of the naturally occurring insecticide, pyrethrum, which comes from Chrysanthemums. Permethrin is used in varying concentrations for agricultural use, treatment of head and body lice on humans, and as an insect repellent. It is repellent to mosquitos, ticks and other insects. Permethrin, when used as an insect repellent, is used on clothing only, not on skin.
Is Permethrin effective as an insect repellent?
YES! Permethrin is an important part of a safe and effective mosquito prevention program. Tests on mosquitoes conducted by the military show that when lightweight uniforms were treated until moist (approximately 4 ½ oz), Permethrin (0.5%) gave 97.7% protection from mosquito bites. Even greater protection was obtained by combining Permethrin applied to clothing with a DEET-based repellent (20-35%) applied to the skin.
Why is Permethrin put on clothing and bed nets?
This product was developed especially for application to clothing. Permethrin bonds to clothing where it remains repellent to insects. Reports vary as to how long treated clothes remain repellent –2 weeks to 6 months (5-20 detergent washings).
Is Permethrin safe?
A temporary, mild skin irritation has been reported in a small number of cases. No serious or long lasting effects have been reported from the use of Permethrin. In the environment, Permethrin readily bonds to soil (and clothing) where it is biodegradable in 1-16 weeks. Permethrin has a low level of toxicity to birds and mammals, but it is highly toxic to insects, bees and fish. For this reason, it is important that residual material does not contaminate blooming crops, waterways or other aquatic areas.
How do I apply Permethrin?
- One can of Permethrin will treat several outfits – shirts, shorts, and socks.
- Spread out all of the clothes to be treated on a flat surface. Hold the can approximately 12inches away from the clothing. Spray the clothing using sweeping motions until the clothing is moist. Pay close attention to cuffs and collars. Turn the clothes over and repeat the process. Hang up the clothes and allow them to dry thoroughly.
- Repellent properties will last longer if clothes are sealed in a resealable plastic bag until use.
- Treat mosquito nets in the same manner as above.
Should I use insect repellant as well as Permethrin?
Yes. Insect repellents containing DEET (N,N –diethyl-meta tolumide) or picaridin, should be used on exposed skin and Permethrin repellents should be used on clothes. The importance of avoiding mosquito bites to avoid mosquito borne illnesses cannot be overemphasized.
Is DEET safe?
The toxicity of DEET is unclear and is still under investigation. It is known that DEET is absorbed by the skin and excreted by the kidneys. It is thought that children absorb more DEET than adults because of the larger skin to body weight ratio.
To minimize DEET absorption, the following precautions are suggested:
- Apply DEET only as frequently as the manufacturer’s recommendation.
- Avoid applying repellents to children’s hands that are likely to have contact with the eyes or mouth.
- Do not drink repellents or get them into the eyes or mouth. Drinking large amounts of DEET can be fatal. Avoid inhaling DEET spray.
- Keep repellents out of open cuts or inflamed or irritated skin.
- Wash off repellents after coming indoors.
- Keep DEET out of the reach of children and make sure that DEET is applied by adults or older teens.
What DEET concentration should be used?
DEET repellents are available in concentrations from 5% to 100%. The higher the concentration of DEET, the longer it repels insects (30% DEET repellents give 4–6 hours of protection).